21015250431 has 16 divisors (see below), whose sum is σ = 32057299968. Its totient is φ = 11995941600.

The previous prime is 21015250411. The next prime is 21015250457. The reversal of 21015250431 is 13405251012.

It is a happy number.

It is not a de Polignac number, because 21015250431 - 2²¹ = 21013153279 is a prime.

It is a super-2 number, since 2×21015250431² (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 (21015250411) 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, 511975 + ... + 551496.

It is an arithmetic number, because the mean of its divisors is an integer number (2003581248).

Almost surely, 2^21015250431 is an apocalyptic number.

21015250431 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21015250431 is a deficient number, since it is larger than the sum of its proper divisors (11042049537).

21015250431 is a wasteful number, since it uses less digits than its factorization.

21015250431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1064422.

The product of its (nonzero) digits is 1200, while the sum is 24.

The spelling of 21015250431 in words is "twenty-one billion, fifteen million, two hundred fifty thousand, four hundred thirty-one".