645979697 has 8 divisors (see below), whose sum is σ = 704900352. Its totient is φ = 587091600.

The previous prime is 645979687. The next prime is 645979709. The reversal of 645979697 is 796979546.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645979697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645979657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54047 + ... + 64907.

It is an arithmetic number, because the mean of its divisors is an integer number (88112544).

Almost surely, 2^645979697 is an apocalyptic number.

It is an amenable number.

645979697 is a deficient number, since it is larger than the sum of its proper divisors (58920655).

645979697 is a wasteful number, since it uses less digits than its factorization.

645979697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16279.

The product of its digits is 25719120, while the sum is 62.

The square root of 645979697 is about 25416.1306457140. The cubic root of 645979697 is about 864.4494907838.

The spelling of 645979697 in words is "six hundred forty-five million, nine hundred seventy-nine thousand, six hundred ninety-seven".