21712691428 has 12 divisors (see below), whose sum is σ = 38055403260. Its totient is φ = 10839719072.

The previous prime is 21712691411. The next prime is 21712691453. The reversal of 21712691428 is 82419621712.

It can be written as a sum of positive squares in 2 ways, for example, as 5087683584 + 16625007844 = 71328^2 + 128938^2 .

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, 4153723 + ... + 4158946.

It is an arithmetic number, because the mean of its divisors is an integer number (3171283605).

Almost surely, 2^21712691428 is an apocalyptic number.

It is an amenable number.

21712691428 is a deficient number, since it is larger than the sum of its proper divisors (16342711832).

21712691428 is a wasteful number, since it uses less digits than its factorization.

21712691428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8313326 (or 8313324 counting only the distinct ones).

The product of its digits is 96768, while the sum is 43.

The spelling of 21712691428 in words is "twenty-one billion, seven hundred twelve million, six hundred ninety-one thousand, four hundred twenty-eight".