20013557 has 2 divisors, whose sum is σ = 20013558. Its totient is φ = 20013556.

The previous prime is 20013547. The next prime is 20013563. The reversal of 20013557 is 75531002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19989841 + 23716 = 4471^2 + 154^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20013557 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20013547) 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, 10006778 + 10006779.

It is an arithmetic number, because the mean of its divisors is an integer number (10006779).

Almost surely, 2^20013557 is an apocalyptic number.

It is an amenable number.

20013557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20013557 is an equidigital number, since it uses as much as digits as its factorization.

20013557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1050, while the sum is 23.

The square root of 20013557 is about 4473.6514169077. The cubic root of 20013557 is about 271.5030800727.

Adding to 20013557 its reverse (75531002), we get a palindrome (95544559).

The spelling of 20013557 in words is "twenty million, thirteen thousand, five hundred fifty-seven".