650979991 has 4 divisors (see below), whose sum is σ = 651203392. Its totient is φ = 650756592.

The previous prime is 650979977. The next prime is 650980007. The reversal of 650979991 is 199979056.

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

It is a cyclic number.

It is not a de Polignac number, because 650979991 - 2¹⁵ = 650947223 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 (650971991) 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, 107271 + ... + 113176.

It is an arithmetic number, because the mean of its divisors is an integer number (162800848).

Almost surely, 2^650979991 is an apocalyptic number.

650979991 is a deficient number, since it is larger than the sum of its proper divisors (223401).

650979991 is a wasteful number, since it uses less digits than its factorization.

650979991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223400.

The product of its (nonzero) digits is 1377810, while the sum is 55.

The square root of 650979991 is about 25514.3095340634. The cubic root of 650979991 is about 866.6742234219.

The spelling of 650979991 in words is "six hundred fifty million, nine hundred seventy-nine thousand, nine hundred ninety-one".