645197194 has 8 divisors (see below), whose sum is σ = 993952548. Its totient is φ = 313879680.

The previous prime is 645197177. The next prime is 645197207. The reversal of 645197194 is 491791546.

It can be written as a sum of positive squares in 2 ways, for example, as 617771025 + 27426169 = 24855^2 + 5237^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4359367 + ... + 4359514.

Almost surely, 2^645197194 is an apocalyptic number.

645197194 is a deficient number, since it is larger than the sum of its proper divisors (348755354).

645197194 is a wasteful number, since it uses less digits than its factorization.

645197194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8718920.

The product of its digits is 272160, while the sum is 46.

The square root of 645197194 is about 25400.7321548022. The cubic root of 645197194 is about 864.1003014629.

The spelling of 645197194 in words is "six hundred forty-five million, one hundred ninety-seven thousand, one hundred ninety-four".