20720885 has 4 divisors (see below), whose sum is σ = 24865068. Its totient is φ = 16576704.

The previous prime is 20720789. The next prime is 20720893. The reversal of 20720885 is 58802702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2937796 + 17783089 = 1714^2 + 4217^2 .

It is a cyclic number.

It is not a de Polignac number, because 20720885 - 2¹² = 20716789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2072084 + ... + 2072093.

It is an arithmetic number, because the mean of its divisors is an integer number (6216267).

Almost surely, 2^20720885 is an apocalyptic number.

It is an amenable number.

20720885 is a deficient number, since it is larger than the sum of its proper divisors (4144183).

20720885 is an equidigital number, since it uses as much as digits as its factorization.

20720885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4144182.

The product of its (nonzero) digits is 8960, while the sum is 32.

The square root of 20720885 is about 4552.0198813274. The cubic root of 20720885 is about 274.6646490711.

The spelling of 20720885 in words is "twenty million, seven hundred twenty thousand, eight hundred eighty-five".