21259097664 has 168 divisors, whose sum is σ = 67542997248. Its totient is φ = 5878010880.

The previous prime is 21259097653. The next prime is 21259097677. The reversal of 21259097664 is 46679095212.

It is a tau number, because it is divible by the number of its divisors (168).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 255202 + ... + 328094.

Almost surely, 2^21259097664 is an apocalyptic number.

21259097664 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 21259097664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33771498624).

21259097664 is an abundant number, since it is smaller than the sum of its proper divisors (46283899584).

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

21259097664 is a wasteful number, since it uses less digits than its factorization.

21259097664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72953 (or 72936 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 51.

The spelling of 21259097664 in words is "twenty-one billion, two hundred fifty-nine million, ninety-seven thousand, six hundred sixty-four".