21881325663 has 20 divisors (see below), whose sum is σ = 32986811880. Its totient is φ = 14453713872.

The previous prime is 21881325611. The next prime is 21881325673. The reversal of 21881325663 is 36652318812.

21881325663 is a `hidden beast` number, since 2 + 1 + 8 + 81 + 3 + 2 + 566 + 3 = 666.

It is not a de Polignac number, because 21881325663 - 2⁸ = 21881325407 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21881325673) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1230345 + ... + 1248002.

It is an arithmetic number, because the mean of its divisors is an integer number (1649340594).

Almost surely, 2^21881325663 is an apocalyptic number.

21881325663 is a deficient number, since it is larger than the sum of its proper divisors (11105486217).

21881325663 is a wasteful number, since it uses less digits than its factorization.

21881325663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2478468 (or 2478459 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

It can be divided in two parts, 218 and 81325663, that added together give a triangular number (81325881 = T₁₂₇₅₃).

The spelling of 21881325663 in words is "twenty-one billion, eight hundred eighty-one million, three hundred twenty-five thousand, six hundred sixty-three".