21664147031 has 2 divisors, whose sum is σ = 21664147032. Its totient is φ = 21664147030.

The previous prime is 21664146991. The next prime is 21664147061. The reversal of 21664147031 is 13074146612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21664147031 - 2⁶ = 21664146967 is a prime.

It is a super-2 number, since 2×21664147031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21664146982 and 21664147000.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21664147061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10832073515 + 10832073516.

It is an arithmetic number, because the mean of its divisors is an integer number (10832073516).

Almost surely, 2^21664147031 is an apocalyptic number.

21664147031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21664147031 is an equidigital number, since it uses as much as digits as its factorization.

21664147031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 35.

The spelling of 21664147031 in words is "twenty-one billion, six hundred sixty-four million, one hundred forty-seven thousand, thirty-one".