646923820 has 48 divisors (see below), whose sum is σ = 1395602208. Its totient is φ = 251758080.

The previous prime is 646923803. The next prime is 646923821. The reversal of 646923820 is 28329646.

It is not an unprimeable number, because it can be changed into a prime (646923821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 240322 + ... + 242998.

It is an arithmetic number, because the mean of its divisors is an integer number (29075046).

Almost surely, 2^646923820 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 646923820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (697801104).

646923820 is an abundant number, since it is smaller than the sum of its proper divisors (748678388).

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

646923820 is a wasteful number, since it uses less digits than its factorization.

646923820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3010 (or 3008 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 40.

The square root of 646923820 is about 25434.6971674522. The cubic root of 646923820 is about 864.8704273155.

The spelling of 646923820 in words is "six hundred forty-six million, nine hundred twenty-three thousand, eight hundred twenty".