21021086688 has 48 divisors (see below), whose sum is σ = 63063262080. Its totient is φ = 6006024576.

The previous prime is 21021086657. The next prime is 21021086699. The reversal of 21021086688 is 88668012012.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15640018 + ... + 15641361.

It is an arithmetic number, because the mean of its divisors is an integer number (1313817960).

Almost surely, 2^21021086688 is an apocalyptic number.

21021086688 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21021086688 is an abundant number, since it is smaller than the sum of its proper divisors (42042175392).

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

21021086688 is a wasteful number, since it uses less digits than its factorization.

21021086688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31281399 (or 31281391 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 42.

The spelling of 21021086688 in words is "twenty-one billion, twenty-one million, eighty-six thousand, six hundred eighty-eight".