20670557 has 2 divisors, whose sum is σ = 20670558. Its totient is φ = 20670556.

The previous prime is 20670547. The next prime is 20670563. The reversal of 20670557 is 75507602.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17480761 + 3189796 = 4181^2 + 1786^2 .

It is a cyclic number.

It is not a de Polignac number, because 20670557 - 2¹⁶ = 20605021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20670547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10335278 + 10335279.

It is an arithmetic number, because the mean of its divisors is an integer number (10335279).

Almost surely, 2^20670557 is an apocalyptic number.

It is an amenable number.

20670557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20670557 is an equidigital number, since it uses as much as digits as its factorization.

20670557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14700, while the sum is 32.

The square root of 20670557 is about 4546.4884251475. The cubic root of 20670557 is about 274.4420953659.

The spelling of 20670557 in words is "twenty million, six hundred seventy thousand, five hundred fifty-seven".