646622791 has 2 divisors, whose sum is σ = 646622792. Its totient is φ = 646622790.

The previous prime is 646622789. The next prime is 646622797. The reversal of 646622791 is 197226646.

It is a happy number.

646622791 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646622791 - 2¹ = 646622789 is a prime.

Together with 646622789, it forms a pair of twin primes.

It is equal to p_33626977 and since 646622791 and 33626977 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646622797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323311395 + 323311396.

It is an arithmetic number, because the mean of its divisors is an integer number (323311396).

Almost surely, 2^646622791 is an apocalyptic number.

646622791 is a deficient number, since it is larger than the sum of its proper divisors (1).

646622791 is an equidigital number, since it uses as much as digits as its factorization.

646622791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 43.

The square root of 646622791 is about 25428.7787949009. The cubic root of 646622791 is about 864.7362582605.

The spelling of 646622791 in words is "six hundred forty-six million, six hundred twenty-two thousand, seven hundred ninety-one".