21149017553664 has 2160 divisors, whose sum is σ = 86682511238400. Its totient is φ = 5062228254720.

The previous prime is 21149017553663. The next prime is 21149017553707. The reversal of 21149017553664 is 46635571094112.

21149017553664 is a `hidden beast` number, since 2 + 1 + 1 + 4 + 90 + 17 + 5 + 536 + 6 + 4 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21149017553664.

It is not an unprimeable number, because it can be changed into a prime (21149017553663) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 35307207637 + ... + 35307208235.

It is an arithmetic number, because the mean of its divisors is an integer number (40130792240).

Almost surely, 2^{21149017553664} is an apocalyptic number.

21149017553664 is a gapful number since it is divisible by the number (24) 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 21149017553664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43341255619200).

21149017553664 is an abundant number, since it is smaller than the sum of its proper divisors (65533493684736).

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

21149017553664 is an frugal number, since it uses more digits than its factorization.

21149017553664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 680 (or 635 counting only the distinct ones).

The product of its (nonzero) digits is 5443200, while the sum is 54.

The spelling of 21149017553664 in words is "twenty-one trillion, one hundred forty-nine billion, seventeen million, five hundred fifty-three thousand, six hundred sixty-four".