21604334431 has 2 divisors, whose sum is σ = 21604334432. Its totient is φ = 21604334430.

The previous prime is 21604334359. The next prime is 21604334441. The reversal of 21604334431 is 13443340612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21604334431 - 2¹¹ = 21604332383 is a prime.

It is a super-2 number, since 2×21604334431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21604334393 and 21604334402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21604334441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802167215 + 10802167216.

It is an arithmetic number, because the mean of its divisors is an integer number (10802167216).

Almost surely, 2^21604334431 is an apocalyptic number.

21604334431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21604334431 is an equidigital number, since it uses as much as digits as its factorization.

21604334431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 31.

The spelling of 21604334431 in words is "twenty-one billion, six hundred four million, three hundred thirty-four thousand, four hundred thirty-one".