21123130031 has 4 divisors (see below), whose sum is σ = 21223239864. Its totient is φ = 21023020200.

The previous prime is 21123130009. The next prime is 21123130051. The reversal of 21123130031 is 13003132112.

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 21123130031 - 2³⁰ = 20049388207 is a prime.

It is a super-2 number, since 2×21123130031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21123129991 and 21123130009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123130051) 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, 50054600 + ... + 50055021.

It is an arithmetic number, because the mean of its divisors is an integer number (5305809966).

Almost surely, 2^21123130031 is an apocalyptic number.

21123130031 is a deficient number, since it is larger than the sum of its proper divisors (100109833).

21123130031 is a wasteful number, since it uses less digits than its factorization.

21123130031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100109832.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21123130031 its reverse (13003132112), we get a palindrome (34126262143).

The spelling of 21123130031 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty thousand, thirty-one".