21253056555536 has 20 divisors (see below), whose sum is σ = 44345319928812. Its totient is φ = 9809103025536.

The previous prime is 21253056555499. The next prime is 21253056555541. The reversal of 21253056555536 is 63555565035212.

It can be written as a sum of positive squares in 2 ways, for example, as 9319099398400 + 11933957157136 = 3052720^2 + 3454556^2 .

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, 51089078051 + ... + 51089078466.

Almost surely, 2^{21253056555536} is an apocalyptic number.

21253056555536 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21253056555536 is an abundant number, since it is smaller than the sum of its proper divisors (23092263373276).

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

21253056555536 is a wasteful number, since it uses less digits than its factorization.

21253056555536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102178156538 (or 102178156532 counting only the distinct ones).

The product of its (nonzero) digits is 20250000, while the sum is 53.

The spelling of 21253056555536 in words is "twenty-one trillion, two hundred fifty-three billion, fifty-six million, five hundred fifty-five thousand, five hundred thirty-six".