21331039 has 4 divisors (see below), whose sum is σ = 22585824. Its totient is φ = 20076256.

The previous prime is 21331021. The next prime is 21331043. The reversal of 21331039 is 93013312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21331039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331049) 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, 627367 + ... + 627400.

It is an arithmetic number, because the mean of its divisors is an integer number (5646456).

Almost surely, 2^21331039 is an apocalyptic number.

21331039 is a deficient number, since it is larger than the sum of its proper divisors (1254785).

21331039 is a wasteful number, since it uses less digits than its factorization.

21331039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1254784.

The product of its (nonzero) digits is 486, while the sum is 22.

The square root of 21331039 is about 4618.5537779699. The cubic root of 21331039 is about 277.3345668720.

The spelling of 21331039 in words is "twenty-one million, three hundred thirty-one thousand, thirty-nine".