649949639 has 2 divisors, whose sum is σ = 649949640. Its totient is φ = 649949638.

The previous prime is 649949621. The next prime is 649949681. The reversal of 649949639 is 936949946.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 649949639 - 2²⁸ = 381514183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649949239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324974819 + 324974820.

It is an arithmetic number, because the mean of its divisors is an integer number (324974820).

Almost surely, 2^649949639 is an apocalyptic number.

649949639 is a deficient number, since it is larger than the sum of its proper divisors (1).

649949639 is an equidigital number, since it uses as much as digits as its factorization.

649949639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11337408, while the sum is 59.

The square root of 649949639 is about 25494.1098883644. The cubic root of 649949639 is about 866.2167331387.

The spelling of 649949639 in words is "six hundred forty-nine million, nine hundred forty-nine thousand, six hundred thirty-nine".