21661252325163 has 96 divisors (see below), whose sum is σ = 35140348938240. Its totient is φ = 12743837568000.

The previous prime is 21661252325087. The next prime is 21661252325183. The reversal of 21661252325163 is 36152325216612.

21661252325163 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 12 + 523 + 2 + 51 + 63 = 666.

It is not a de Polignac number, because 21661252325163 - 2¹² = 21661252321067 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21661252325183) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1281494970 + ... + 1281511872.

It is an arithmetic number, because the mean of its divisors is an integer number (366045301440).

Almost surely, 2^{21661252325163} is an apocalyptic number.

21661252325163 is a deficient number, since it is larger than the sum of its proper divisors (13479096613077).

21661252325163 is a wasteful number, since it uses less digits than its factorization.

21661252325163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18521 (or 18518 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

The spelling of 21661252325163 in words is "twenty-one trillion, six hundred sixty-one billion, two hundred fifty-two million, three hundred twenty-five thousand, one hundred sixty-three".