21040031424 has 28 divisors (see below), whose sum is σ = 55668416984. Its totient is φ = 7013343744.

The previous prime is 21040031393. The next prime is 21040031429. The reversal of 21040031424 is 42413004012.

It is a self number, because there is not a number n which added to its sum of digits gives 21040031424.

It is not an unprimeable number, because it can be changed into a prime (21040031429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54791557 + ... + 54791940.

Almost surely, 2^21040031424 is an apocalyptic number.

21040031424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21040031424 is an abundant number, since it is smaller than the sum of its proper divisors (34628385560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21040031424 is a wasteful number, since it uses less digits than its factorization.

21040031424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109583512 (or 109583502 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 21040031424 its reverse (42413004012), we get a palindrome (63453035436).

The spelling of 21040031424 in words is "twenty-one billion, forty million, thirty-one thousand, four hundred twenty-four".