21400420432 has 40 divisors (see below), whose sum is σ = 41654733480. Its totient is φ = 10650931200.

The previous prime is 21400420429. The next prime is 21400420463. The reversal of 21400420432 is 23402400412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 11496986176 + 9903434256 = 107224^2 + 99516^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3262468 + ... + 3269020.

It is an arithmetic number, because the mean of its divisors is an integer number (1041368337).

Almost surely, 2^21400420432 is an apocalyptic number.

It is an amenable number.

21400420432 is a deficient number, since it is larger than the sum of its proper divisors (20254313048).

21400420432 is a wasteful number, since it uses less digits than its factorization.

21400420432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7471 (or 7465 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21400420432 its reverse (23402400412), we get a palindrome (44802820844).

The spelling of 21400420432 in words is "twenty-one billion, four hundred million, four hundred twenty thousand, four hundred thirty-two".