20871265 has 8 divisors (see below), whose sum is σ = 25229160. Its totient is φ = 16574592.

The previous prime is 20871251. The next prime is 20871283. The reversal of 20871265 is 56217802.

It can be written as a sum of positive squares in 4 ways, for example, as 2825761 + 18045504 = 1681^2 + 4248^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20871265 - 2⁹ = 20870753 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14550 + ... + 15919.

It is an arithmetic number, because the mean of its divisors is an integer number (3153645).

Almost surely, 2^20871265 is an apocalyptic number.

It is an amenable number.

20871265 is a deficient number, since it is larger than the sum of its proper divisors (4357895).

20871265 is a wasteful number, since it uses less digits than its factorization.

20871265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30611.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 20871265 is about 4568.5079621251. The cubic root of 20871265 is about 275.3274996305.

The spelling of 20871265 in words is "twenty million, eight hundred seventy-one thousand, two hundred sixty-five".