21123230331 has 16 divisors (see below), whose sum is σ = 32422731264. Its totient is φ = 11982310464.

The previous prime is 21123230321. The next prime is 21123230341. The reversal of 21123230331 is 13303232112.

It is an interprime number because it is at equal distance from previous prime (21123230321) and next prime (21123230341).

It is not a de Polignac number, because 21123230331 - 2⁷ = 21123230203 is a prime.

It is a super-2 number, since 2×21123230331² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 21123230298 and 21123230307.

It is not an unprimeable number, because it can be changed into a prime (21123230311) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3668175 + ... + 3673928.

It is an arithmetic number, because the mean of its divisors is an integer number (2026420704).

Almost surely, 2^21123230331 is an apocalyptic number.

21123230331 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21123230331 is a deficient number, since it is larger than the sum of its proper divisors (11299500933).

21123230331 is a wasteful number, since it uses less digits than its factorization.

21123230331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7342250.

The product of its (nonzero) digits is 648, while the sum is 21.

Adding to 21123230331 its reverse (13303232112), we get a palindrome (34426462443).

The spelling of 21123230331 in words is "twenty-one billion, one hundred twenty-three million, two hundred thirty thousand, three hundred thirty-one".