649990765 has 4 divisors (see below), whose sum is σ = 779988924. Its totient is φ = 519992608.

The previous prime is 649990739. The next prime is 649990769. The reversal of 649990765 is 567099946.

649990765 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 407192041 + 242798724 = 20179^2 + 15582^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649990765 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649990769) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64999072 + ... + 64999081.

It is an arithmetic number, because the mean of its divisors is an integer number (194997231).

Almost surely, 2^649990765 is an apocalyptic number.

It is an amenable number.

649990765 is a deficient number, since it is larger than the sum of its proper divisors (129998159).

649990765 is a wasteful number, since it uses less digits than its factorization.

649990765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129998158.

The product of its (nonzero) digits is 3674160, while the sum is 55.

The square root of 649990765 is about 25494.9164540698. The cubic root of 649990765 is about 866.2350029019.

The spelling of 649990765 in words is "six hundred forty-nine million, nine hundred ninety thousand, seven hundred sixty-five".