646462991 has 2 divisors, whose sum is σ = 646462992. Its totient is φ = 646462990.

The previous prime is 646462969. The next prime is 646463017. The reversal of 646462991 is 199264646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646462991 - 2¹⁰ = 646461967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646462931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323231495 + 323231496.

It is an arithmetic number, because the mean of its divisors is an integer number (323231496).

Almost surely, 2^646462991 is an apocalyptic number.

646462991 is a deficient number, since it is larger than the sum of its proper divisors (1).

646462991 is an equidigital number, since it uses as much as digits as its factorization.

646462991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 47.

The square root of 646462991 is about 25425.6364915414. The cubic root of 646462991 is about 864.6650182523.

The spelling of 646462991 in words is "six hundred forty-six million, four hundred sixty-two thousand, nine hundred ninety-one".