21231112031 has 16 divisors (see below), whose sum is σ = 23670804960. Its totient is φ = 18924410880.

The previous prime is 21231112027. The next prime is 21231112039. The reversal of 21231112031 is 13021113212.

It is not a de Polignac number, because 21231112031 - 2² = 21231112027 is a prime.

It is a super-2 number, since 2×21231112031² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231112039) 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, 1206065 + ... + 1223541.

It is an arithmetic number, because the mean of its divisors is an integer number (1479425310).

Almost surely, 2^21231112031 is an apocalyptic number.

21231112031 is a deficient number, since it is larger than the sum of its proper divisors (2439692929).

21231112031 is a wasteful number, since it uses less digits than its factorization.

21231112031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21274.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21231112031 its reverse (13021113212), we get a palindrome (34252225243).

The spelling of 21231112031 in words is "twenty-one billion, two hundred thirty-one million, one hundred twelve thousand, thirty-one".