647646491 has 2 divisors, whose sum is σ = 647646492. Its totient is φ = 647646490.

The previous prime is 647646469. The next prime is 647646553. The reversal of 647646491 is 194646746.

647646491 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 a de Polignac number, because none of the positive numbers 2^k-647646491 is a prime.

It is a super-2 number, since 2×647646491² = 838891954609226162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (647646401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323823245 + 323823246.

It is an arithmetic number, because the mean of its divisors is an integer number (323823246).

Almost surely, 2^647646491 is an apocalyptic number.

647646491 is a deficient number, since it is larger than the sum of its proper divisors (1).

647646491 is an equidigital number, since it uses as much as digits as its factorization.

647646491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 47.

The square root of 647646491 is about 25448.8996029298. The cubic root of 647646491 is about 865.1923530038.

The spelling of 647646491 in words is "six hundred forty-seven million, six hundred forty-six thousand, four hundred ninety-one".