646407216 has 480 divisors, whose sum is σ = 2434219200. Its totient is φ = 164602368.

The previous prime is 646407211. The next prime is 646407241. The reversal of 646407216 is 612704646.

646407216 = 18³ + 19³ + ... + 225³.

646407216 is a `hidden beast` number, since 6 + 4 + 640 + 7 + 2 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646407211) 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, 22289890 + ... + 22289918.

It is an arithmetic number, because the mean of its divisors is an integer number (5071290).

Almost surely, 2^646407216 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 646407216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1217109600).

646407216 is an abundant number, since it is smaller than the sum of its proper divisors (1787811984).

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

646407216 is a wasteful number, since it uses less digits than its factorization.

646407216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85 (or 54 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 646407216 is about 25424.5396418500. The cubic root of 646407216 is about 864.6401505857.

The spelling of 646407216 in words is "six hundred forty-six million, four hundred seven thousand, two hundred sixteen".