20870845 has 16 divisors (see below), whose sum is σ = 26092080. Its totient is φ = 16012800.

The previous prime is 20870813. The next prime is 20870869. The reversal of 20870845 is 54807802.

It can be written as a sum of positive squares in 8 ways, for example, as 7409284 + 13461561 = 2722^2 + 3669^2 .

It is not a de Polignac number, because 20870845 - 2⁵ = 20870813 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20870845.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11671 + ... + 13339.

It is an arithmetic number, because the mean of its divisors is an integer number (1630755).

Almost surely, 2^20870845 is an apocalyptic number.

It is an amenable number.

20870845 is a deficient number, since it is larger than the sum of its proper divisors (5221235).

20870845 is a wasteful number, since it uses less digits than its factorization.

20870845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1776.

The product of its (nonzero) digits is 17920, while the sum is 34.

The square root of 20870845 is about 4568.4619950263. The cubic root of 20870845 is about 275.3256527799.

The spelling of 20870845 in words is "twenty million, eight hundred seventy thousand, eight hundred forty-five".