646823980 has 48 divisors (see below), whose sum is σ = 1499710464. Its totient is φ = 232368320.

The previous prime is 646823977. The next prime is 646823993. The reversal of 646823980 is 89328646.

It is a happy number.

It is a super-2 number, since 2×646823980² = 836762522206080800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 646823980.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 549 + ... + 35971.

It is an arithmetic number, because the mean of its divisors is an integer number (31243968).

Almost surely, 2^646823980 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646823980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (749855232).

646823980 is an abundant number, since it is smaller than the sum of its proper divisors (852886484).

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

646823980 is a wasteful number, since it uses less digits than its factorization.

646823980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35526 (or 35524 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 46.

The square root of 646823980 is about 25432.7344184616. The cubic root of 646823980 is about 864.8259330988.

The spelling of 646823980 in words is "six hundred forty-six million, eight hundred twenty-three thousand, nine hundred eighty".