21690845128 has 32 divisors (see below), whose sum is σ = 40896316800. Its totient is φ = 10785310528.

The previous prime is 21690845117. The next prime is 21690845147. The reversal of 21690845128 is 82154809612.

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 7 ways as a sum of consecutive naturals, for example, 1202625 + ... + 1220527.

It is an arithmetic number, because the mean of its divisors is an integer number (1278009900).

Almost surely, 2^21690845128 is an apocalyptic number.

It is an amenable number.

21690845128 is a deficient number, since it is larger than the sum of its proper divisors (19205471672).

21690845128 is a wasteful number, since it uses less digits than its factorization.

21690845128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18741 (or 18737 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 46.

The spelling of 21690845128 in words is "twenty-one billion, six hundred ninety million, eight hundred forty-five thousand, one hundred twenty-eight".