665515553 has 2 divisors, whose sum is σ = 665515554. Its totient is φ = 665515552.

The previous prime is 665515481. The next prime is 665515561. The reversal of 665515553 is 355515566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 383846464 + 281669089 = 19592^2 + 16783^2 .

It is a cyclic number.

It is not a de Polignac number, because 665515553 - 2¹⁰ = 665514529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 665515553.

It is not a weakly prime, because it can be changed into another prime (665515583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332757776 + 332757777.

It is an arithmetic number, because the mean of its divisors is an integer number (332757777).

Almost surely, 2^665515553 is an apocalyptic number.

It is an amenable number.

665515553 is a deficient number, since it is larger than the sum of its proper divisors (1).

665515553 is an equidigital number, since it uses as much as digits as its factorization.

665515553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 337500, while the sum is 41.

The square root of 665515553 is about 25797.5881236987. The cubic root of 665515553 is about 873.0773798652.

The spelling of 665515553 in words is "six hundred sixty-five million, five hundred fifteen thousand, five hundred fifty-three".