645205698 has 12 divisors (see below), whose sum is σ = 1397945718. Its totient is φ = 215068560.

The previous prime is 645205663. The next prime is 645205721. The reversal of 645205698 is 896502546.

645205698 is a `hidden beast` number, since 64 + 5 + 20 + 569 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 586269369 + 58936329 = 24213^2 + 7677^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17922363 + ... + 17922398.

Almost surely, 2^645205698 is an apocalyptic number.

645205698 is an abundant number, since it is smaller than the sum of its proper divisors (752740020).

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

645205698 is a wasteful number, since it uses less digits than its factorization.

645205698 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35844769 (or 35844766 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The square root of 645205698 is about 25400.8995510002. The cubic root of 645205698 is about 864.1040978612.

The spelling of 645205698 in words is "six hundred forty-five million, two hundred five thousand, six hundred ninety-eight".