650644991 has 2 divisors, whose sum is σ = 650644992. Its totient is φ = 650644990.

The previous prime is 650644919. The next prime is 650644993. The reversal of 650644991 is 199446056.

Together with previous prime (650644919) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 650644991 - 2²⁶ = 583536127 is a prime.

Together with 650644993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (650644993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325322495 + 325322496.

It is an arithmetic number, because the mean of its divisors is an integer number (325322496).

Almost surely, 2^650644991 is an apocalyptic number.

650644991 is a deficient number, since it is larger than the sum of its proper divisors (1).

650644991 is an equidigital number, since it uses as much as digits as its factorization.

650644991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 233280, while the sum is 44.

The square root of 650644991 is about 25507.7437457726. The cubic root of 650644991 is about 866.5255318665.

The spelling of 650644991 in words is "six hundred fifty million, six hundred forty-four thousand, nine hundred ninety-one".