646989620 has 12 divisors (see below), whose sum is σ = 1358678244. Its totient is φ = 258795840.

The previous prime is 646989613. The next prime is 646989641. The reversal of 646989620 is 26989646.

It can be written as a sum of positive squares in 2 ways, for example, as 78357904 + 568631716 = 8852^2 + 23846^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16174721 + ... + 16174760.

It is an arithmetic number, because the mean of its divisors is an integer number (113223187).

Almost surely, 2^646989620 is an apocalyptic number.

It is an amenable number.

646989620 is an abundant number, since it is smaller than the sum of its proper divisors (711688624).

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

646989620 is a wasteful number, since it uses less digits than its factorization.

646989620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32349490 (or 32349488 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 50.

The square root of 646989620 is about 25435.9906431812. The cubic root of 646989620 is about 864.8997489260.

The spelling of 646989620 in words is "six hundred forty-six million, nine hundred eighty-nine thousand, six hundred twenty".