15556865940 has 864 divisors, whose sum is σ = 63884177280. Its totient is φ = 3129477120.

The previous prime is 15556865921. The next prime is 15556865941. The reversal of 15556865940 is 4956865551.

15556865940 is a `hidden beast` number, since 1 + 5 + 556 + 86 + 5 + 9 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15556865941) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 137671324 + ... + 137671436.

It is an arithmetic number, because the mean of its divisors is an integer number (73940020).

Almost surely, 2^15556865940 is an apocalyptic number.

15556865940 is a gapful number since it is divisible by the number (10) 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 15556865940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31942088640).

15556865940 is an abundant number, since it is smaller than the sum of its proper divisors (48327311340).

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

15556865940 is a wasteful number, since it uses less digits than its factorization.

15556865940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 6480000, while the sum is 54.

The spelling of 15556865940 in words is "fifteen billion, five hundred fifty-six million, eight hundred sixty-five thousand, nine hundred forty".