21402651663 has 12 divisors (see below), whose sum is σ = 30952334088. Its totient is φ = 14251176240.

The previous prime is 21402651617. The next prime is 21402651667. The reversal of 21402651663 is 36615620412.

21402651663 is a `hidden beast` number, since 21 + 40 + 26 + 516 + 63 = 666.

It is not a de Polignac number, because 21402651663 - 2⁸ = 21402651407 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402651667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1430328 + ... + 1445213.

It is an arithmetic number, because the mean of its divisors is an integer number (2579361174).

Almost surely, 2^21402651663 is an apocalyptic number.

21402651663 is a deficient number, since it is larger than the sum of its proper divisors (9549682425).

21402651663 is a wasteful number, since it uses less digits than its factorization.

21402651663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2876374 (or 2876371 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

It can be divided in two parts, 2140265166 and 3, that added together give a square (2140265169 = 46263²).

The spelling of 21402651663 in words is "twenty-one billion, four hundred two million, six hundred fifty-one thousand, six hundred sixty-three".