645905022 has 64 divisors (see below), whose sum is σ = 1503774720. Its totient is φ = 181142784.

The previous prime is 645904979. The next prime is 645905047. The reversal of 645905022 is 220509546.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 897979 + ... + 898697.

It is an arithmetic number, because the mean of its divisors is an integer number (23496480).

Almost surely, 2^645905022 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645905022, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (751887360).

645905022 is an abundant number, since it is smaller than the sum of its proper divisors (857869698).

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

645905022 is a wasteful number, since it uses less digits than its factorization.

645905022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1097.

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 645905022 is about 25414.6615558815. The cubic root of 645905022 is about 864.4161794926.

The spelling of 645905022 in words is "six hundred forty-five million, nine hundred five thousand, twenty-two".