21659863680 has 1152 divisors, whose sum is σ = 97331794560. Its totient is φ = 4319723520.

The previous prime is 21659863663. The next prime is 21659863697. The reversal of 21659863680 is 8636895612.

It is a happy number.

21659863680 is a `hidden beast` number, since 2 + 16 + 598 + 6 + 36 + 8 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21659863663) and next prime (21659863697).

It is a tau number, because it is divible by the number of its divisors (1152).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 503717739 + ... + 503717781.

It is an arithmetic number, because the mean of its divisors is an integer number (84489405).

Almost surely, 2^21659863680 is an apocalyptic number.

21659863680 is a gapful number since it is divisible by the number (20) 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 21659863680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48665897280).

21659863680 is an abundant number, since it is smaller than the sum of its proper divisors (75671930880).

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

21659863680 is a wasteful number, since it uses less digits than its factorization.

21659863680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 104 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

The spelling of 21659863680 in words is "twenty-one billion, six hundred fifty-nine million, eight hundred sixty-three thousand, six hundred eighty".