649252391 has 4 divisors (see below), whose sum is σ = 649965984. Its totient is φ = 648538800.

The previous prime is 649252381. The next prime is 649252397. The reversal of 649252391 is 193252946.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649252391 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 (649252397) 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, 355430 + ... + 357251.

It is an arithmetic number, because the mean of its divisors is an integer number (162491496).

Almost surely, 2^649252391 is an apocalyptic number.

649252391 is a deficient number, since it is larger than the sum of its proper divisors (713593).

649252391 is an equidigital number, since it uses as much as digits as its factorization.

649252391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713592.

The product of its digits is 116640, while the sum is 41.

The square root of 649252391 is about 25480.4315308827. The cubic root of 649252391 is about 865.9068711891.

The spelling of 649252391 in words is "six hundred forty-nine million, two hundred fifty-two thousand, three hundred ninety-one".