15661654991136 has 2592 divisors, whose sum is σ = 63341620272000. Its totient is φ = 3749411635200.

The previous prime is 15661654991131. The next prime is 15661654991141. The reversal of 15661654991136 is 63119945616651.

15661654991136 is a `hidden beast` number, since 1 + 5 + 6 + 6 + 1 + 6 + 5 + 499 + 1 + 136 = 666.

It is an interprime number because it is at equal distance from previous prime (15661654991131) and next prime (15661654991141).

It is a super-2 number, since 2×15661654991136² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (15661654991131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 431 ways as a sum of consecutive naturals, for example, 105111778390 + ... + 105111778538.

It is an arithmetic number, because the mean of its divisors is an integer number (24437353500).

Almost surely, 2^{15661654991136} is an apocalyptic number.

15661654991136 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15661654991136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31670810136000).

15661654991136 is an abundant number, since it is smaller than the sum of its proper divisors (47679965280864).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15661654991136 is a wasteful number, since it uses less digits than its factorization.

15661654991136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 260 counting only the distinct ones).

The product of its digits is 31492800, while the sum is 63.

The spelling of 15661654991136 in words is "fifteen trillion, six hundred sixty-one billion, six hundred fifty-four million, nine hundred ninety-one thousand, one hundred thirty-six".