661660230625 has 15 divisors (see below), whose sum is σ = 826836036367. Its totient is φ = 529311916000.

The previous prime is 661660230577. The next prime is 661660230653. The reversal of 661660230625 is 526032066166.

The square root of 661660230625 is 813425.

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 627591930849 + 34068299776 = 792207^2 + 184576^2 .

It is not a de Polignac number, because 661660230625 - 2¹⁵ = 661660197857 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 20319357 + ... + 20351893.

Almost surely, 2^661660230625 is an apocalyptic number.

661660230625 is the 813425-th square number.

661660230625 is the 406713-rd centered octagonal number.

It is an amenable number.

661660230625 is a deficient number, since it is larger than the sum of its proper divisors (165175805742).

661660230625 is an frugal number, since it uses more digits than its factorization.

661660230625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65094 (or 32542 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 43.

The spelling of 661660230625 in words is "six hundred sixty-one billion, six hundred sixty million, two hundred thirty thousand, six hundred twenty-five".