666736308225 has 36 divisors (see below), whose sum is σ = 1286060262396. Its totient is φ = 328239411840.

The previous prime is 666736308221. The next prime is 666736308239. The reversal of 666736308225 is 522803637666.

It can be written as a sum of positive squares in 6 ways, for example, as 7195789584 + 659540518641 = 84828^2 + 812121^2 .

It is not a de Polignac number, because 666736308225 - 2² = 666736308221 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666736308221) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 113969094 + ... + 113974943.

Almost surely, 2^666736308225 is an apocalyptic number.

666736308225 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

666736308225 is a deficient number, since it is larger than the sum of its proper divisors (619323954171).

666736308225 is a wasteful number, since it uses less digits than its factorization.

666736308225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227944066 (or 227944058 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 54.

The spelling of 666736308225 in words is "six hundred sixty-six billion, seven hundred thirty-six million, three hundred eight thousand, two hundred twenty-five".