21005621496 has 96 divisors (see below), whose sum is σ = 57172021920. Its totient is φ = 6967296000.

The previous prime is 21005621489. The next prime is 21005621501. The reversal of 21005621496 is 69412650012.

21005621496 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 562 + 1 + 4 + 96 = 666.

It is a super-2 number, since 2×21005621496² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21005621496.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18217656 + ... + 18218808.

It is an arithmetic number, because the mean of its divisors is an integer number (595541895).

Almost surely, 2^21005621496 is an apocalyptic number.

It is an amenable number.

21005621496 is an abundant number, since it is smaller than the sum of its proper divisors (36166400424).

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

21005621496 is a wasteful number, since it uses less digits than its factorization.

21005621496 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2197 (or 2190 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21005621496 in words is "twenty-one billion, five million, six hundred twenty-one thousand, four hundred ninety-six".