21663553031 has 2 divisors, whose sum is σ = 21663553032. Its totient is φ = 21663553030.

The previous prime is 21663552991. The next prime is 21663553111. The reversal of 21663553031 is 13035536612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21663553031 - 2¹⁰ = 21663552007 is a prime.

It is a super-2 number, since 2×21663553031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21663552982 and 21663553000.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21663553231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10831776515 + 10831776516.

It is an arithmetic number, because the mean of its divisors is an integer number (10831776516).

Almost surely, 2^21663553031 is an apocalyptic number.

21663553031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21663553031 is an equidigital number, since it uses as much as digits as its factorization.

21663553031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48600, while the sum is 35.

The spelling of 21663553031 in words is "twenty-one billion, six hundred sixty-three million, five hundred fifty-three thousand, thirty-one".