646757647 has 12 divisors (see below), whose sum is σ = 666916416. Its totient is φ = 627152960.

The previous prime is 646757621. The next prime is 646757651. The reversal of 646757647 is 746757646.

It is not a de Polignac number, because 646757647 - 2⁷ = 646757519 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 646757594 and 646757603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646757047) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 248322 + ... + 250912.

It is an arithmetic number, because the mean of its divisors is an integer number (55576368).

Almost surely, 2^646757647 is an apocalyptic number.

646757647 is a deficient number, since it is larger than the sum of its proper divisors (20158769).

646757647 is a wasteful number, since it uses less digits than its factorization.

646757647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2798 (or 2751 counting only the distinct ones).

The product of its digits is 5927040, while the sum is 52.

The square root of 646757647 is about 25431.4302979600. The cubic root of 646757647 is about 864.7963689199.

Subtracting 646757647 from its reverse (746757646), we obtain a palindrome (99999999).

The spelling of 646757647 in words is "six hundred forty-six million, seven hundred fifty-seven thousand, six hundred forty-seven".