646022640 has 120 divisors (see below), whose sum is σ = 2070095184. Its totient is φ = 166656000.

The previous prime is 646022639. The next prime is 646022659. The reversal of 646022640 is 46220646.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 646022598 and 646022607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 229240 + ... + 232040.

Almost surely, 2^646022640 is an apocalyptic number.

646022640 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 646022640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1035047592).

646022640 is an abundant number, since it is smaller than the sum of its proper divisors (1424072544).

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

646022640 is a wasteful number, since it uses less digits than its factorization.

646022640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2879 (or 2842 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 646022640 is about 25416.9754298186. The cubic root of 646022640 is about 864.4686457882.

The spelling of 646022640 in words is "six hundred forty-six million, twenty-two thousand, six hundred forty".