645994250 has 32 divisors (see below), whose sum is σ = 1319243328. Its totient is φ = 234906000.

The previous prime is 645994247. The next prime is 645994253. The reversal of 645994250 is 52499546.

It is an interprime number because it is at equal distance from previous prime (645994247) and next prime (645994253).

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (645994253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114704 + ... + 120203.

It is an arithmetic number, because the mean of its divisors is an integer number (41226354).

Almost surely, 2^645994250 is an apocalyptic number.

645994250 is an abundant number, since it is smaller than the sum of its proper divisors (673249078).

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

645994250 is a wasteful number, since it uses less digits than its factorization.

645994250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234935 (or 234925 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 44.

The square root of 645994250 is about 25416.4169386639. The cubic root of 645994250 is about 864.4559823392.

The spelling of 645994250 in words is "six hundred forty-five million, nine hundred ninety-four thousand, two hundred fifty".