21036438 has 24 divisors (see below), whose sum is σ = 45840600. Its totient is φ = 6971904.

The previous prime is 21036413. The next prime is 21036443. The reversal of 21036438 is 83463012.

It is a happy number.

21036438 is a `hidden beast` number, since 2 + 10 + 3 + 643 + 8 = 666.

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 11 ways as a sum of consecutive naturals, for example, 43 + ... + 6486.

It is an arithmetic number, because the mean of its divisors is an integer number (1910025).

Almost surely, 2^21036438 is an apocalyptic number.

21036438 is an abundant number, since it is smaller than the sum of its proper divisors (24804162).

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

21036438 is a wasteful number, since it uses less digits than its factorization.

21036438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6716 (or 6713 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21036438 is about 4586.5496835857. The cubic root of 21036438 is about 276.0518963535.

The spelling of 21036438 in words is "twenty-one million, thirty-six thousand, four hundred thirty-eight".