665704232649 has 9 divisors (see below), whose sum is σ = 961576316103. Its totient is φ = 443801189952.

The previous prime is 665704232603. The next prime is 665704232657. The reversal of 665704232649 is 946232407566.

The square root of 665704232649 is 815907.

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

665704232649 is a `hidden beast` number, since 6 + 6 + 570 + 4 + 2 + 3 + 2 + 64 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 221188674249 + 444515558400 = 470307^2 + 666720^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 665704232649 - 2¹⁹ = 665703708361 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 665704232595 and 665704232604.

It is not an unprimeable number, because it can be changed into a prime (665704232689) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2311737 + ... + 2583705.

Almost surely, 2^665704232649 is an apocalyptic number.

665704232649 is the 815907-th square number.

665704232649 is the 407954-th centered octagonal number.

It is an amenable number.

665704232649 is a deficient number, since it is larger than the sum of its proper divisors (295872083454).

665704232649 is an frugal number, since it uses more digits than its factorization.

665704232649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543944 (or 271972 counting only the distinct ones).

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

The spelling of 665704232649 in words is "six hundred sixty-five billion, seven hundred four million, two hundred thirty-two thousand, six hundred forty-nine".