21004131023 has 4 divisors (see below), whose sum is σ = 22239668160. Its totient is φ = 19768593888.

The previous prime is 21004131017. The next prime is 21004131041. The reversal of 21004131023 is 32013140012.

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

It is not a de Polignac number, because 21004131023 - 2³² = 16709163727 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1235537119 = 21004131023 / (2 + 1 + 0 + 0 + 4 + 1 + 3 + 1 + 0 + 2 + 3).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21004130992 and 21004131010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004131013) 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, 617768543 + ... + 617768576.

It is an arithmetic number, because the mean of its divisors is an integer number (5559917040).

Almost surely, 2^21004131023 is an apocalyptic number.

21004131023 is a deficient number, since it is larger than the sum of its proper divisors (1235537137).

21004131023 is a wasteful number, since it uses less digits than its factorization.

21004131023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235537136.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21004131023 its reverse (32013140012), we get a palindrome (53017271035).

The spelling of 21004131023 in words is "twenty-one billion, four million, one hundred thirty-one thousand, twenty-three".