21210017502128 has 40 divisors (see below), whose sum is σ = 50577734047008. Its totient is φ = 8390776154112.

The previous prime is 21210017502049. The next prime is 21210017502139. The reversal of 21210017502128 is 82120571001212.

It is a junction number, because it is equal to n+sod(n) for n = 21210017502094 and 21210017502103.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7283658401 + ... + 7283661312.

Almost surely, 2^{21210017502128} is an apocalyptic number.

21210017502128 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21210017502128 is an abundant number, since it is smaller than the sum of its proper divisors (29367716544880).

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

21210017502128 is a wasteful number, since it uses less digits than its factorization.

21210017502128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14567319741 (or 14567319735 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 32.

The spelling of 21210017502128 in words is "twenty-one trillion, two hundred ten billion, seventeen million, five hundred two thousand, one hundred twenty-eight".