649640664 has 24 divisors (see below), whose sum is σ = 1759443660. Its totient is φ = 216546864.

The previous prime is 649640653. The next prime is 649640671. The reversal of 649640664 is 466046946.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4511322 + ... + 4511465.

Almost surely, 2^649640664 is an apocalyptic number.

It is an amenable number.

649640664 is an abundant number, since it is smaller than the sum of its proper divisors (1109802996).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

649640664 is a wasteful number, since it uses less digits than its factorization.

649640664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9022799 (or 9022792 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 45.

The square root of 649640664 is about 25488.0494349803. The cubic root of 649640664 is about 866.0794498167.

The spelling of 649640664 in words is "six hundred forty-nine million, six hundred forty thousand, six hundred sixty-four".