20557711 has 2 divisors, whose sum is σ = 20557712. Its totient is φ = 20557710.

The previous prime is 20557697. The next prime is 20557721. The reversal of 20557711 is 11775502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20557711 - 2⁷ = 20557583 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20557711.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20557721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278855 + 10278856.

It is an arithmetic number, because the mean of its divisors is an integer number (10278856).

Almost surely, 2^20557711 is an apocalyptic number.

20557711 is a deficient number, since it is larger than the sum of its proper divisors (1).

20557711 is an equidigital number, since it uses as much as digits as its factorization.

20557711 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 20557711 is about 4534.0612038216. The cubic root of 20557711 is about 273.9417666218.

The spelling of 20557711 in words is "twenty million, five hundred fifty-seven thousand, seven hundred eleven".