20864015 has 16 divisors (see below), whose sum is σ = 26619840. Its totient is φ = 15644160.

The previous prime is 20864009. The next prime is 20864047. The reversal of 20864015 is 51046802.

It is a de Polignac number, because none of the positive numbers 2^k-20864015 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32750 + ... + 33380.

It is an arithmetic number, because the mean of its divisors is an integer number (1663740).

Almost surely, 2^20864015 is an apocalyptic number.

20864015 is a deficient number, since it is larger than the sum of its proper divisors (5755825).

20864015 is a wasteful number, since it uses less digits than its factorization.

20864015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 20864015 is about 4567.7144175178. The cubic root of 20864015 is about 275.2956159929.

The spelling of 20864015 in words is "twenty million, eight hundred sixty-four thousand, fifteen".