646735761 has 45 divisors (see below), whose sum is σ = 1096140539. Its totient is φ = 367427088.

The previous prime is 646735759. The next prime is 646735769. The reversal of 646735761 is 167537646.

The square root of 646735761 is 25431.

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

646735761 is a `hidden beast` number, since 6 + 4 + 6 + 73 + 576 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 588305025 + 58430736 = 24255^2 + 7644^2 .

It is not a de Polignac number, because 646735761 - 2¹ = 646735759 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646735769) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 3738271 + ... + 3738443.

Almost surely, 2^646735761 is an apocalyptic number.

646735761 is the 25431-st square number.

646735761 is the 12716-th centered octagonal number.

It is an amenable number.

646735761 is a deficient number, since it is larger than the sum of its proper divisors (449404778).

646735761 is an frugal number, since it uses more digits than its factorization.

646735761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380 (or 183 counting only the distinct ones).

The product of its digits is 635040, while the sum is 45.

The cubic root of 646735761 is about 864.7866140310.

The spelling of 646735761 in words is "six hundred forty-six million, seven hundred thirty-five thousand, seven hundred sixty-one".