20655857 has 2 divisors, whose sum is σ = 20655858. Its totient is φ = 20655856.

The previous prime is 20655853. The next prime is 20655871. The reversal of 20655857 is 75855602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20647936 + 7921 = 4544^2 + 89^2 .

It is a cyclic number.

It is not a de Polignac number, because 20655857 - 2² = 20655853 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20655857.

It is not a weakly prime, because it can be changed into another prime (20655853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10327928 + 10327929.

It is an arithmetic number, because the mean of its divisors is an integer number (10327929).

Almost surely, 2^20655857 is an apocalyptic number.

It is an amenable number.

20655857 is a deficient number, since it is larger than the sum of its proper divisors (1).

20655857 is an equidigital number, since it uses as much as digits as its factorization.

20655857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84000, while the sum is 38.

The square root of 20655857 is about 4544.8715053343. The cubic root of 20655857 is about 274.3770228489.

It can be divided in two parts, 20655 and 857, that added together give a palindrome (21512).

The spelling of 20655857 in words is "twenty million, six hundred fifty-five thousand, eight hundred fifty-seven".