21023121231 has 48 divisors (see below), whose sum is σ = 35947591680. Its totient is φ = 11585695680.

The previous prime is 21023121167. The next prime is 21023121233. The reversal of 21023121231 is 13212132012.

It is not a de Polignac number, because 21023121231 - 2⁶ = 21023121167 is a prime.

It is a super-2 number, since 2×21023121231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023121233) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 553860 + ... + 590598.

It is an arithmetic number, because the mean of its divisors is an integer number (748908160).

Almost surely, 2^21023121231 is an apocalyptic number.

21023121231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21023121231 is a deficient number, since it is larger than the sum of its proper divisors (14924470449).

21023121231 is a wasteful number, since it uses less digits than its factorization.

21023121231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37076 (or 37073 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21023121231 its reverse (13212132012), we get a palindrome (34235253243).

The spelling of 21023121231 in words is "twenty-one billion, twenty-three million, one hundred twenty-one thousand, two hundred thirty-one".