646549816 has 16 divisors (see below), whose sum is σ = 1322488440. Its totient is φ = 293886240.

The previous prime is 646549811. The next prime is 646549817. The reversal of 646549816 is 618945646.

It is a self number, because there is not a number n which added to its sum of digits gives 646549816.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646549811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3673491 + ... + 3673666.

Almost surely, 2^646549816 is an apocalyptic number.

It is an amenable number.

646549816 is an abundant number, since it is smaller than the sum of its proper divisors (675938624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646549816 is a wasteful number, since it uses less digits than its factorization.

646549816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7347174 (or 7347170 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 49.

The square root of 646549816 is about 25427.3438644307. The cubic root of 646549816 is about 864.7037269283.

The spelling of 646549816 in words is "six hundred forty-six million, five hundred forty-nine thousand, eight hundred sixteen".