21012334431 has 16 divisors (see below), whose sum is σ = 30673746048. Its totient is φ = 12688768800.

The previous prime is 21012334423. The next prime is 21012334433. The reversal of 21012334431 is 13443321012.

It is a happy number.

It is not a de Polignac number, because 21012334431 - 2³ = 21012334423 is a prime.

It is a super-2 number, since 2×21012334431² (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 (21012334433) 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, 1140205 + ... + 1158486.

It is an arithmetic number, because the mean of its divisors is an integer number (1917109128).

Almost surely, 2^21012334431 is an apocalyptic number.

21012334431 is a deficient number, since it is larger than the sum of its proper divisors (9661411617).

21012334431 is a wasteful number, since it uses less digits than its factorization.

21012334431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2298982.

The product of its (nonzero) digits is 1728, while the sum is 24.

Adding to 21012334431 its reverse (13443321012), we get a palindrome (34455655443).

The spelling of 21012334431 in words is "twenty-one billion, twelve million, three hundred thirty-four thousand, four hundred thirty-one".