645813598 has 4 divisors (see below), whose sum is σ = 968720400. Its totient is φ = 322906798.

The previous prime is 645813583. The next prime is 645813617. The reversal of 645813598 is 895318546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 895318546 = 2 ⋅447659273.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161453398 + ... + 161453401.

It is an arithmetic number, because the mean of its divisors is an integer number (242180100).

Almost surely, 2^645813598 is an apocalyptic number.

645813598 is a deficient number, since it is larger than the sum of its proper divisors (322906802).

645813598 is a wasteful number, since it uses less digits than its factorization.

645813598 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322906801.

The product of its digits is 1036800, while the sum is 49.

The square root of 645813598 is about 25412.8628454175. The cubic root of 645813598 is about 864.3753932516.

The spelling of 645813598 in words is "six hundred forty-five million, eight hundred thirteen thousand, five hundred ninety-eight".