21020012431 has 12 divisors (see below), whose sum is σ = 23115659616. Its totient is φ = 19099989920.

The previous prime is 21020012413. The next prime is 21020012449. The reversal of 21020012431 is 13421002012.

It is an interprime number because it is at equal distance from previous prime (21020012413) and next prime (21020012449).

It is not a de Polignac number, because 21020012431 - 2⁵ = 21020012399 is a prime.

It is a super-2 number, since 2×21020012431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020012231) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 220170 + ... + 300856.

It is an arithmetic number, because the mean of its divisors is an integer number (1926304968).

Almost surely, 2^21020012431 is an apocalyptic number.

21020012431 is a deficient number, since it is larger than the sum of its proper divisors (2095647185).

21020012431 is a wasteful number, since it uses less digits than its factorization.

21020012431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82862 (or 82851 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21020012431 its reverse (13421002012), we get a palindrome (34441014443).

The spelling of 21020012431 in words is "twenty-one billion, twenty million, twelve thousand, four hundred thirty-one".