668739595225 has 81 divisors (see below), whose sum is σ = 940388367933. Its totient is φ = 471503672640.

The previous prime is 668739595201. The next prime is 668739595243. The reversal of 668739595225 is 522595937866.

The square root of 668739595225 is 817765.

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

It can be written as a sum of positive squares in 4 ways, for example, as 172368619929 + 496370975296 = 415173^2 + 704536^2 .

It is not a de Polignac number, because 668739595225 - 2¹¹ = 668739593177 is a prime.

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, 1222558402 + ... + 1222558948.

Almost surely, 2^668739595225 is an apocalyptic number.

668739595225 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

668739595225 is the 817765-th square number.

668739595225 is the 408883-rd centered octagonal number.

It is an amenable number.

668739595225 is a deficient number, since it is larger than the sum of its proper divisors (271648772708).

668739595225 is an equidigital number, since it uses as much as digits as its factorization.

668739595225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1176 (or 588 counting only the distinct ones).

The product of its digits is 244944000, while the sum is 67.

The spelling of 668739595225 in words is "six hundred sixty-eight billion, seven hundred thirty-nine million, five hundred ninety-five thousand, two hundred twenty-five".