21372429817 has 4 divisors (see below), whose sum is σ = 22301665920. Its totient is φ = 20443193716.

The previous prime is 21372429809. The next prime is 21372429833. The reversal of 21372429817 is 71892427312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21372429817 - 2³ = 21372429809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21372429877) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 464618017 + ... + 464618062.

It is an arithmetic number, because the mean of its divisors is an integer number (5575416480).

Almost surely, 2^21372429817 is an apocalyptic number.

It is an amenable number.

21372429817 is a deficient number, since it is larger than the sum of its proper divisors (929236103).

21372429817 is an equidigital number, since it uses as much as digits as its factorization.

21372429817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 929236102.

The product of its digits is 338688, while the sum is 46.

The spelling of 21372429817 in words is "twenty-one billion, three hundred seventy-two million, four hundred twenty-nine thousand, eight hundred seventeen".