649565509 has 4 divisors (see below), whose sum is σ = 661821516. Its totient is φ = 637309504.

The previous prime is 649565489. The next prime is 649565549. The reversal of 649565509 is 905565946.

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 368064225 + 281501284 = 19185^2 + 16778^2 .

It is a cyclic number.

It is not a de Polignac number, because 649565509 - 2⁷ = 649565381 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 (649565549) 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, 6127924 + ... + 6128029.

It is an arithmetic number, because the mean of its divisors is an integer number (165455379).

Almost surely, 2^649565509 is an apocalyptic number.

It is an amenable number.

649565509 is a deficient number, since it is larger than the sum of its proper divisors (12256007).

649565509 is a wasteful number, since it uses less digits than its factorization.

649565509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12256006.

The product of its (nonzero) digits is 1458000, while the sum is 49.

The square root of 649565509 is about 25486.5750739482. The cubic root of 649565509 is about 866.0460504752.

The spelling of 649565509 in words is "six hundred forty-nine million, five hundred sixty-five thousand, five hundred nine".