21232553939 has 2 divisors, whose sum is σ = 21232553940. Its totient is φ = 21232553938.

The previous prime is 21232553911. The next prime is 21232553959. The reversal of 21232553939 is 93935523212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21232553939 - 2²⁴ = 21215776723 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21232553939.

It is not a weakly prime, because it can be changed into another prime (21232553959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616276969 + 10616276970.

It is an arithmetic number, because the mean of its divisors is an integer number (10616276970).

Almost surely, 2^21232553939 is an apocalyptic number.

21232553939 is a deficient number, since it is larger than the sum of its proper divisors (1).

21232553939 is an equidigital number, since it uses as much as digits as its factorization.

21232553939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 437400, while the sum is 44.

The spelling of 21232553939 in words is "twenty-one billion, two hundred thirty-two million, five hundred fifty-three thousand, nine hundred thirty-nine".