21389382 has 36 divisors (see below), whose sum is σ = 53912196. Its totient is φ = 6111000.

The previous prime is 21389377. The next prime is 21389393. The reversal of 21389382 is 28398312.

It is a happy number.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 11244 + ... + 13007.

It is an arithmetic number, because the mean of its divisors is an integer number (1497561).

Almost surely, 2^21389382 is an apocalyptic number.

21389382 is an abundant number, since it is smaller than the sum of its proper divisors (32522814).

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

21389382 is a wasteful number, since it uses less digits than its factorization.

21389382 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24273 (or 24263 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 21389382 is about 4624.8656196694. The cubic root of 21389382 is about 277.5871846825.

It can be divided in two parts, 21 and 389382, that added together give a triangular number (389403 = T₈₈₂).

The spelling of 21389382 in words is "twenty-one million, three hundred eighty-nine thousand, three hundred eighty-two".