646887761 has 16 divisors (see below), whose sum is σ = 718397904. Its totient is φ = 578617344.

The previous prime is 646887751. The next prime is 646887781. The reversal of 646887761 is 167788646.

646887761 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 242113600 + 404774161 = 15560^2 + 20119^2 .

It is a cyclic number.

It is not a de Polignac number, because 646887761 - 2⁶ = 646887697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646887751) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 121001 + ... + 126233.

It is an arithmetic number, because the mean of its divisors is an integer number (44899869).

Almost surely, 2^646887761 is an apocalyptic number.

It is an amenable number.

646887761 is a deficient number, since it is larger than the sum of its proper divisors (71510143).

646887761 is a wasteful number, since it uses less digits than its factorization.

646887761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5540.

The product of its digits is 2709504, while the sum is 53.

The square root of 646887761 is about 25433.9883030562. The cubic root of 646887761 is about 864.8543579623.

The spelling of 646887761 in words is "six hundred forty-six million, eight hundred eighty-seven thousand, seven hundred sixty-one".