645508694 has 4 divisors (see below), whose sum is σ = 968263044. Its totient is φ = 322754346.

The previous prime is 645508663. The next prime is 645508711. The reversal of 645508694 is 496805546.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161377172 + ... + 161377175.

It is an arithmetic number, because the mean of its divisors is an integer number (242065761).

Almost surely, 2^645508694 is an apocalyptic number.

645508694 is a deficient number, since it is larger than the sum of its proper divisors (322754350).

645508694 is a wasteful number, since it uses less digits than its factorization.

645508694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322754349.

The product of its (nonzero) digits is 1036800, while the sum is 47.

The square root of 645508694 is about 25406.8631279031. The cubic root of 645508694 is about 864.2393410930.

The spelling of 645508694 in words is "six hundred forty-five million, five hundred eight thousand, six hundred ninety-four".