21231431431 has 16 divisors (see below), whose sum is σ = 25363598400. Its totient is φ = 17754495360.

The previous prime is 21231431411. The next prime is 21231431447. The reversal of 21231431431 is 13413413212.

It is not a de Polignac number, because 21231431431 - 2⁹ = 21231430919 is a prime.

It is a super-2 number, since 2×21231431431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21231431396 and 21231431405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231431411) 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, 740806 + ... + 768931.

It is an arithmetic number, because the mean of its divisors is an integer number (1585224900).

Almost surely, 2^21231431431 is an apocalyptic number.

21231431431 is a deficient number, since it is larger than the sum of its proper divisors (4132166969).

21231431431 is an equidigital number, since it uses as much as digits as its factorization.

21231431431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1509799 (or 1509785 counting only the distinct ones).

The product of its digits is 1728, while the sum is 25.

Adding to 21231431431 its reverse (13413413212), we get a palindrome (34644844643).

The spelling of 21231431431 in words is "twenty-one billion, two hundred thirty-one million, four hundred thirty-one thousand, four hundred thirty-one".