21002344431 has 16 divisors (see below), whose sum is σ = 29747414400. Its totient is φ = 13142940768.

The previous prime is 21002344427. The next prime is 21002344463. The reversal of 21002344431 is 13444320012.

It is not a de Polignac number, because 21002344431 - 2² = 21002344427 is a prime.

It is a super-2 number, since 2×21002344431² (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 (21002344421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1683981 + ... + 1696406.

It is an arithmetic number, because the mean of its divisors is an integer number (1859213400).

Almost surely, 2^21002344431 is an apocalyptic number.

21002344431 is a deficient number, since it is larger than the sum of its proper divisors (8745069969).

21002344431 is a wasteful number, since it uses less digits than its factorization.

21002344431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3380518.

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21002344431 its reverse (13444320012), we get a palindrome (34446664443).

The spelling of 21002344431 in words is "twenty-one billion, two million, three hundred forty-four thousand, four hundred thirty-one".