21104039 has 4 divisors (see below), whose sum is σ = 23022600. Its totient is φ = 19185480.

The previous prime is 21104033. The next prime is 21104059. The reversal of 21104039 is 93040112.

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

It is a cyclic number.

It is not a de Polignac number, because 21104039 - 2¹² = 21099943 is a prime.

It is a super-2 number, since 2×21104039² = 890760924227042, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21104039.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104033) 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, 959264 + ... + 959285.

It is an arithmetic number, because the mean of its divisors is an integer number (5755650).

Almost surely, 2^21104039 is an apocalyptic number.

21104039 is a deficient number, since it is larger than the sum of its proper divisors (1918561).

21104039 is a wasteful number, since it uses less digits than its factorization.

21104039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1918560.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21104039 is about 4593.9132556025. The cubic root of 21104039 is about 276.3472795402.

The spelling of 21104039 in words is "twenty-one million, one hundred four thousand, thirty-nine".