646880795520 has 256 divisors, whose sum is σ = 2126440512000. Its totient is φ = 167187292160.

The previous prime is 646880795497. The next prime is 646880795527. The reversal of 646880795520 is 25597088646.

It is a Cunningham number, because it is equal to 804289²-1.

It is a super-2 number, since 2×646880795520² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646880795527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8002666 + ... + 8083094.

It is an arithmetic number, because the mean of its divisors is an integer number (8306408250).

Almost surely, 2^646880795520 is an apocalyptic number.

646880795520 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 646880795520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1063220256000).

646880795520 is an abundant number, since it is smaller than the sum of its proper divisors (1479559716480).

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

646880795520 is a wasteful number, since it uses less digits than its factorization.

646880795520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80581 (or 80569 counting only the distinct ones).

The product of its (nonzero) digits is 29030400, while the sum is 60.

The spelling of 646880795520 in words is "six hundred forty-six billion, eight hundred eighty million, seven hundred ninety-five thousand, five hundred twenty".