645739193 has 4 divisors (see below), whose sum is σ = 704442768. Its totient is φ = 587035620.

The previous prime is 645739189. The next prime is 645739219. The reversal of 645739193 is 391937546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645739193 - 2² = 645739189 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645739123) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 29351771 + ... + 29351792.

It is an arithmetic number, because the mean of its divisors is an integer number (176110692).

Almost surely, 2^645739193 is an apocalyptic number.

It is an amenable number.

645739193 is a deficient number, since it is larger than the sum of its proper divisors (58703575).

645739193 is a wasteful number, since it uses less digits than its factorization.

645739193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58703574.

The product of its digits is 612360, while the sum is 47.

The square root of 645739193 is about 25411.3988792431. The cubic root of 645739193 is about 864.3421967166.

The spelling of 645739193 in words is "six hundred forty-five million, seven hundred thirty-nine thousand, one hundred ninety-three".