21317818423 has 16 divisors (see below), whose sum is σ = 25472892960. Its totient is φ = 17610880000.

The previous prime is 21317818411. The next prime is 21317818447. The reversal of 21317818423 is 32481871312.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21317818423 is a prime.

It is a super-4 number, since 4×21317818423⁴ (a number of 42 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21317818723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1960078 + ... + 1970923.

It is an arithmetic number, because the mean of its divisors is an integer number (1592055810).

Almost surely, 2^21317818423 is an apocalyptic number.

21317818423 is a deficient number, since it is larger than the sum of its proper divisors (4155074537).

21317818423 is a wasteful number, since it uses less digits than its factorization.

21317818423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3931058.

The product of its digits is 64512, while the sum is 40.

The spelling of 21317818423 in words is "twenty-one billion, three hundred seventeen million, eight hundred eighteen thousand, four hundred twenty-three".