21105039 has 8 divisors (see below), whose sum is σ = 28319920. Its totient is φ = 13980096.

The previous prime is 21105023. The next prime is 21105043. The reversal of 21105039 is 93050112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21105039 - 2⁴ = 21105023 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 (21105239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21934 + ... + 22875.

It is an arithmetic number, because the mean of its divisors is an integer number (3539990).

Almost surely, 2^21105039 is an apocalyptic number.

21105039 is a deficient number, since it is larger than the sum of its proper divisors (7214881).

21105039 is a wasteful number, since it uses less digits than its factorization.

21105039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44969.

The product of its (nonzero) digits is 270, while the sum is 21.

The square root of 21105039 is about 4594.0220939826. The cubic root of 21105039 is about 276.3516443116.

The spelling of 21105039 in words is "twenty-one million, one hundred five thousand, thirty-nine".