21621361431663 has 24 divisors (see below), whose sum is σ = 37244249922048. Its totient is φ = 11817886992912.

The previous prime is 21621361431647. The next prime is 21621361431757. The reversal of 21621361431663 is 36613416312612.

21621361431663 is a `hidden beast` number, since 2 + 1 + 6 + 2 + 13 + 614 + 3 + 16 + 6 + 3 = 666.

It is not a de Polignac number, because 21621361431663 - 2⁴ = 21621361431647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621361631663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7460785795 + ... + 7460788692.

It is an arithmetic number, because the mean of its divisors is an integer number (1551843746752).

Almost surely, 2^{21621361431663} is an apocalyptic number.

21621361431663 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21621361431663 is a deficient number, since it is larger than the sum of its proper divisors (15622888490385).

21621361431663 is a wasteful number, since it uses less digits than its factorization.

21621361431663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14921574523 (or 14921574520 counting only the distinct ones).

The product of its digits is 559872, while the sum is 45.

The spelling of 21621361431663 in words is "twenty-one trillion, six hundred twenty-one billion, three hundred sixty-one million, four hundred thirty-one thousand, six hundred sixty-three".