649813257 has 6 divisors (see below), whose sum is σ = 938619162. Its totient is φ = 433208832.

The previous prime is 649813217. The next prime is 649813259. The reversal of 649813257 is 752318946.

It can be written as a sum of positive squares in only one way, i.e., 398241936 + 251571321 = 19956^2 + 15861^2 .

It is not a de Polignac number, because 649813257 - 2⁶ = 649813193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (649813259) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36100728 + ... + 36100745.

It is an arithmetic number, because the mean of its divisors is an integer number (156436527).

Almost surely, 2^649813257 is an apocalyptic number.

It is an amenable number.

649813257 is a deficient number, since it is larger than the sum of its proper divisors (288805905).

649813257 is a wasteful number, since it uses less digits than its factorization.

649813257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72201479 (or 72201476 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 649813257 is about 25491.4349733396. The cubic root of 649813257 is about 866.1561414521.

The spelling of 649813257 in words is "six hundred forty-nine million, eight hundred thirteen thousand, two hundred fifty-seven".