20660857 has 8 divisors (see below), whose sum is σ = 23965376. Its totient is φ = 17444592.

The previous prime is 20660851. The next prime is 20660869. The reversal of 20660857 is 75806602.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20660857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20660851) by changing a digit.

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, 21558 + ... + 22495.

It is an arithmetic number, because the mean of its divisors is an integer number (2995672).

Almost surely, 2^20660857 is an apocalyptic number.

It is an amenable number.

20660857 is a deficient number, since it is larger than the sum of its proper divisors (3304519).

20660857 is an equidigital number, since it uses as much as digits as its factorization.

20660857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44127.

The product of its (nonzero) digits is 20160, while the sum is 34.

The square root of 20660857 is about 4545.4215426075. The cubic root of 20660857 is about 274.3991598217.

The spelling of 20660857 in words is "twenty million, six hundred sixty thousand, eight hundred fifty-seven".