21042749831 has 32 divisors (see below), whose sum is σ = 22887951360. Its totient is φ = 19284604416.

The previous prime is 21042749797. The next prime is 21042749837. The reversal of 21042749831 is 13894724012.

It is a cyclic number.

It is not a de Polignac number, because 21042749831 - 2²⁶ = 20975640967 is a prime.

It is a super-2 number, since 2×21042749831² (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 (21042749837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34104635 + ... + 34105251.

It is an arithmetic number, because the mean of its divisors is an integer number (715248480).

Almost surely, 2^21042749831 is an apocalyptic number.

21042749831 is a deficient number, since it is larger than the sum of its proper divisors (1845201529).

21042749831 is a wasteful number, since it uses less digits than its factorization.

21042749831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1143.

The product of its (nonzero) digits is 96768, while the sum is 41.

The spelling of 21042749831 in words is "twenty-one billion, forty-two million, seven hundred forty-nine thousand, eight hundred thirty-one".