20700857 has 4 divisors (see below), whose sum is σ = 20725236. Its totient is φ = 20676480.

The previous prime is 20700833. The next prime is 20700887. The reversal of 20700857 is 75800702.

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 9916201 + 10784656 = 3149^2 + 3284^2 .

It is a cyclic number.

It is not a de Polignac number, because 20700857 - 2¹² = 20696761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20700817) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 10868 + ... + 12629.

It is an arithmetic number, because the mean of its divisors is an integer number (5181309).

Almost surely, 2^20700857 is an apocalyptic number.

It is an amenable number.

20700857 is a deficient number, since it is larger than the sum of its proper divisors (24379).

20700857 is an equidigital number, since it uses as much as digits as its factorization.

20700857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24378.

The product of its (nonzero) digits is 3920, while the sum is 29.

The square root of 20700857 is about 4549.8194469671. The cubic root of 20700857 is about 274.5761271621.

The spelling of 20700857 in words is "twenty million, seven hundred thousand, eight hundred fifty-seven".