666794730625 has 45 divisors (see below), whose sum is σ = 844996410687. Its totient is φ = 526004952000.

The previous prime is 666794730601. The next prime is 666794730629. The reversal of 666794730625 is 526037497666.

The square root of 666794730625 is 816575.

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

It can be written as a sum of positive squares in 7 ways, for example, as 647752938561 + 19041792064 = 804831^2 + 137992^2 .

It is not a de Polignac number, because 666794730625 - 2²¹ = 666792633473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666794730629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1816879192 + ... + 1816879558.

Almost surely, 2^666794730625 is an apocalyptic number.

666794730625 is the 816575-th square number.

666794730625 is the 408288-th centered octagonal number.

It is an amenable number.

666794730625 is a deficient number, since it is larger than the sum of its proper divisors (178201680062).

666794730625 is an frugal number, since it uses more digits than its factorization.

666794730625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 932 (or 461 counting only the distinct ones).

The product of its (nonzero) digits is 68584320, while the sum is 61.

The spelling of 666794730625 in words is "six hundred sixty-six billion, seven hundred ninety-four million, seven hundred thirty thousand, six hundred twenty-five".