20606557 has 2 divisors, whose sum is σ = 20606558. Its totient is φ = 20606556.

The previous prime is 20606527. The next prime is 20606563. The reversal of 20606557 is 75560602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12432676 + 8173881 = 3526^2 + 2859^2 .

It is a cyclic number.

It is not a de Polignac number, because 20606557 - 2⁷ = 20606429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20606527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10303278 + 10303279.

It is an arithmetic number, because the mean of its divisors is an integer number (10303279).

Almost surely, 2^20606557 is an apocalyptic number.

It is an amenable number.

20606557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20606557 is an equidigital number, since it uses as much as digits as its factorization.

20606557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 31.

The square root of 20606557 is about 4539.4445695481. Note that the first 3 decimals coincide. The cubic root of 20606557 is about 274.1585607903.

The spelling of 20606557 in words is "twenty million, six hundred six thousand, five hundred fifty-seven".