21235431376 has 20 divisors (see below), whose sum is σ = 41145974500. Its totient is φ = 10617115392.

The previous prime is 21235431353. The next prime is 21235431389. The reversal of 21235431376 is 67313453212.

It can be written as a sum of positive squares in 2 ways, for example, as 6149696400 + 15085734976 = 78420^2 + 122824^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 433540 + ... + 480028.

It is an arithmetic number, because the mean of its divisors is an integer number (2057298725).

Almost surely, 2^21235431376 is an apocalyptic number.

It is an amenable number.

21235431376 is a deficient number, since it is larger than the sum of its proper divisors (19910543124).

21235431376 is a wasteful number, since it uses less digits than its factorization.

21235431376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75046 (or 75040 counting only the distinct ones).

The product of its digits is 90720, while the sum is 37.

Adding to 21235431376 its reverse (67313453212), we get a palindrome (88548884588).

The spelling of 21235431376 in words is "twenty-one billion, two hundred thirty-five million, four hundred thirty-one thousand, three hundred seventy-six".