21315666960 has 240 divisors, whose sum is σ = 84451261440. Its totient is φ = 4714951680.

The previous prime is 21315666941. The next prime is 21315666979. The reversal of 21315666960 is 6966651312.

It is an interprime number because it is at equal distance from previous prime (21315666941) and next prime (21315666979).

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

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 47 ways as a sum of consecutive naturals, for example, 88026 + ... + 224454.

It is an arithmetic number, because the mean of its divisors is an integer number (351880256).

Almost surely, 2^21315666960 is an apocalyptic number.

21315666960 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 21315666960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42225630720).

21315666960 is an abundant number, since it is smaller than the sum of its proper divisors (63135594480).

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

21315666960 is a wasteful number, since it uses less digits than its factorization.

21315666960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136486 (or 136477 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 45.

The spelling of 21315666960 in words is "twenty-one billion, three hundred fifteen million, six hundred sixty-six thousand, nine hundred sixty".