21305812940 has 12 divisors (see below), whose sum is σ = 44742207216. Its totient is φ = 8522325168.

The previous prime is 21305812937. The next prime is 21305812951. The reversal of 21305812940 is 4921850312.

It is a self number, because there is not a number n which added to its sum of digits gives 21305812940.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 532645304 + ... + 532645343.

It is an arithmetic number, because the mean of its divisors is an integer number (3728517268).

Almost surely, 2^21305812940 is an apocalyptic number.

21305812940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21305812940 is an abundant number, since it is smaller than the sum of its proper divisors (23436394276).

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

21305812940 is a wasteful number, since it uses less digits than its factorization.

21305812940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1065290656 (or 1065290654 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 35.

The spelling of 21305812940 in words is "twenty-one billion, three hundred five million, eight hundred twelve thousand, nine hundred forty".