21311010023 has 4 divisors (see below), whose sum is σ = 21328239240. Its totient is φ = 21293780808.

The previous prime is 21311010011. The next prime is 21311010073. The reversal of 21311010023 is 32001011312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21311010023 - 2¹⁸ = 21310747879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311010073) 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, 8612753 + ... + 8615226.

It is an arithmetic number, because the mean of its divisors is an integer number (5332059810).

Almost surely, 2^21311010023 is an apocalyptic number.

21311010023 is a deficient number, since it is larger than the sum of its proper divisors (17229217).

21311010023 is a wasteful number, since it uses less digits than its factorization.

21311010023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17229216.

The product of its (nonzero) digits is 36, while the sum is 14.

Adding to 21311010023 its reverse (32001011312), we get a palindrome (53312021335).

The spelling of 21311010023 in words is "twenty-one billion, three hundred eleven million, ten thousand, twenty-three".