645998788 has 24 divisors (see below), whose sum is σ = 1177716960. Its totient is φ = 309775680.

The previous prime is 645998779. The next prime is 645998789. The reversal of 645998788 is 887899546.

It is not an unprimeable number, because it can be changed into a prime (645998789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23706 + ... + 43057.

It is an arithmetic number, because the mean of its divisors is an integer number (49071540).

Almost surely, 2^645998788 is an apocalyptic number.

It is an amenable number.

645998788 is a deficient number, since it is larger than the sum of its proper divisors (531718172).

645998788 is a wasteful number, since it uses less digits than its factorization.

645998788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66867 (or 66865 counting only the distinct ones).

The product of its digits is 34836480, while the sum is 64.

The square root of 645998788 is about 25416.5062115154. The cubic root of 645998788 is about 864.4580065533.

The spelling of 645998788 in words is "six hundred forty-five million, nine hundred ninety-eight thousand, seven hundred eighty-eight".