646624220 has 48 divisors (see below), whose sum is σ = 1496075616. Its totient is φ = 232800000.

The previous prime is 646624211. The next prime is 646624229. The reversal of 646624220 is 22426646.

It is an interprime number because it is at equal distance from previous prime (646624211) and next prime (646624229).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646624229) 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, 7670 + ... + 36770.

It is an arithmetic number, because the mean of its divisors is an integer number (31168242).

Almost surely, 2^646624220 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 646624220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (748037808).

646624220 is an abundant number, since it is smaller than the sum of its proper divisors (849451396).

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

646624220 is a wasteful number, since it uses less digits than its factorization.

646624220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29222 (or 29220 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 646624220 is about 25428.8068929708. The cubic root of 646624220 is about 864.7368952662.

The spelling of 646624220 in words is "six hundred forty-six million, six hundred twenty-four thousand, two hundred twenty".