20553557 has 2 divisors, whose sum is σ = 20553558. Its totient is φ = 20553556.

The previous prime is 20553529. The next prime is 20553569. The reversal of 20553557 is 75535502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12453841 + 8099716 = 3529^2 + 2846^2 .

It is a cyclic number.

It is not a de Polignac number, because 20553557 - 2⁸ = 20553301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20553517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10276778 + 10276779.

It is an arithmetic number, because the mean of its divisors is an integer number (10276779).

Almost surely, 2^20553557 is an apocalyptic number.

It is an amenable number.

20553557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20553557 is an equidigital number, since it uses as much as digits as its factorization.

20553557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26250, while the sum is 32.

The square root of 20553557 is about 4533.6030924641. The cubic root of 20553557 is about 273.9233140039.

The spelling of 20553557 in words is "twenty million, five hundred fifty-three thousand, five hundred fifty-seven".