21389396 has 12 divisors (see below), whose sum is σ = 42778848. Its totient is φ = 9166872.

The previous prime is 21389393. The next prime is 21389419. The reversal of 21389396 is 69398312.

21389396 is an admirable number.

It is a super-2 number, since 2×21389396² = 915012522489632, which contains 22 as substring.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21389393) 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, 381926 + ... + 381981.

It is an arithmetic number, because the mean of its divisors is an integer number (3564904).

Almost surely, 2^21389396 is an apocalyptic number.

It is an amenable number.

21389396 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21389396 is a wasteful number, since it uses less digits than its factorization.

21389396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763918 (or 763916 counting only the distinct ones).

The product of its digits is 69984, while the sum is 41.

The square root of 21389396 is about 4624.8671332266. The cubic root of 21389396 is about 277.5872452455.

The spelling of 21389396 in words is "twenty-one million, three hundred eighty-nine thousand, three hundred ninety-six".