645035994 has 64 divisors (see below), whose sum is σ = 1471841280. Its totient is φ = 209326320.

The previous prime is 645035983. The next prime is 645035999. The reversal of 645035994 is 499530546.

645035994 is a `hidden beast` number, since 6 + 4 + 50 + 3 + 599 + 4 = 666.

It is not an unprimeable number, because it can be changed into a prime (645035999) 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, 317209 + ... + 319235.

It is an arithmetic number, because the mean of its divisors is an integer number (22997520).

Almost surely, 2^645035994 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645035994, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (735920640).

645035994 is an abundant number, since it is smaller than the sum of its proper divisors (826805286).

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

645035994 is a wasteful number, since it uses less digits than its factorization.

645035994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2192 (or 2186 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 45.

The square root of 645035994 is about 25397.5588196976. The cubic root of 645035994 is about 864.0283314398.

The spelling of 645035994 in words is "six hundred forty-five million, thirty-five thousand, nine hundred ninety-four".