21605372339431 has 2 divisors, whose sum is σ = 21605372339432. Its totient is φ = 21605372339430.

The previous prime is 21605372339423. The next prime is 21605372339533. The reversal of 21605372339431 is 13493327350612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21605372339431 - 2³ = 21605372339423 is a prime.

It is a super-2 number, since 2×21605372339431² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21605372339731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802686169715 + 10802686169716.

It is an arithmetic number, because the mean of its divisors is an integer number (10802686169716).

Almost surely, 2^{21605372339431} is an apocalyptic number.

21605372339431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21605372339431 is an equidigital number, since it uses as much as digits as its factorization.

21605372339431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2449440, while the sum is 49.

The spelling of 21605372339431 in words is "twenty-one trillion, six hundred five billion, three hundred seventy-two million, three hundred thirty-nine thousand, four hundred thirty-one".