663581306025 has 81 divisors (see below), whose sum is σ = 1306685036293. Its totient is φ = 321671222400.

The previous prime is 663581305997. The next prime is 663581306033. The reversal of 663581306025 is 520603185366.

The square root of 663581306025 is 814605.

It is a perfect power (a square), and thus also a powerful number.

663581306025 is a `hidden beast` number, since 6 + 6 + 3 + 5 + 8 + 1 + 30 + 602 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 28136372121 + 635444933904 = 167739^2 + 797148^2 .

It is not a de Polignac number, because 663581306025 - 2¹⁷ = 663581174953 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 134407357 + ... + 134412293.

Almost surely, 2^663581306025 is an apocalyptic number.

663581306025 is the 814605-th square number.

663581306025 is the 407303-rd centered octagonal number.

It is an amenable number.

663581306025 is a deficient number, since it is larger than the sum of its proper divisors (643103730268).

663581306025 is an equidigital number, since it uses as much as digits as its factorization.

663581306025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9912 (or 4956 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 663581306025 in words is "six hundred sixty-three billion, five hundred eighty-one million, three hundred six thousand, twenty-five".