20541557 has 2 divisors, whose sum is σ = 20541558. Its totient is φ = 20541556.

The previous prime is 20541523. The next prime is 20541571. The reversal of 20541557 is 75514502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19307236 + 1234321 = 4394^2 + 1111^2 .

It is a cyclic number.

It is not a de Polignac number, because 20541557 - 2²⁰ = 19492981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20541757) 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 as a sum of consecutive naturals, namely, 10270778 + 10270779.

It is an arithmetic number, because the mean of its divisors is an integer number (10270779).

Almost surely, 2^20541557 is an apocalyptic number.

It is an amenable number.

20541557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20541557 is an equidigital number, since it uses as much as digits as its factorization.

20541557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7000, while the sum is 29.

The square root of 20541557 is about 4532.2794485777. The cubic root of 20541557 is about 273.8699944466.

The spelling of 20541557 in words is "twenty million, five hundred forty-one thousand, five hundred fifty-seven".