646507680 has 576 divisors, whose sum is σ = 2709842688. Its totient is φ = 126074880.

The previous prime is 646507657. The next prime is 646507681. The reversal of 646507680 is 86705646.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (646507681) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15768460 + ... + 15768500.

It is an arithmetic number, because the mean of its divisors is an integer number (4704588).

Almost surely, 2^646507680 is an apocalyptic number.

646507680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646507680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1354921344).

646507680 is an abundant number, since it is smaller than the sum of its proper divisors (2063335008).

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

646507680 is a wasteful number, since it uses less digits than its factorization.

646507680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 42.

The square root of 646507680 is about 25426.5152940783. The cubic root of 646507680 is about 864.6849421176.

The spelling of 646507680 in words is "six hundred forty-six million, five hundred seven thousand, six hundred eighty".