21042144431 has 12 divisors (see below), whose sum is σ = 26702833320. Its totient is φ = 16396475760.

The previous prime is 21042144427. The next prime is 21042144457. The reversal of 21042144431 is 13444124012.

It is not a de Polignac number, because 21042144431 - 2² = 21042144427 is a prime.

It is a super-2 number, since 2×21042144431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21042144431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042144731) 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 11 ways as a sum of consecutive naturals, for example, 19519076 + ... + 19520153.

It is an arithmetic number, because the mean of its divisors is an integer number (2225236110).

Almost surely, 2^21042144431 is an apocalyptic number.

21042144431 is a deficient number, since it is larger than the sum of its proper divisors (5660688889).

21042144431 is a wasteful number, since it uses less digits than its factorization.

21042144431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39039254 (or 39039247 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

Adding to 21042144431 its reverse (13444124012), we get a palindrome (34486268443).

The spelling of 21042144431 in words is "twenty-one billion, forty-two million, one hundred forty-four thousand, four hundred thirty-one".