645599823 has 8 divisors (see below), whose sum is σ = 939054336. Its totient is φ = 391272600.

The previous prime is 645599819. The next prime is 645599839. The reversal of 645599823 is 328995546.

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

It is not a de Polignac number, because 645599823 - 2² = 645599819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645599863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9781783 + ... + 9781848.

It is an arithmetic number, because the mean of its divisors is an integer number (117381792).

Almost surely, 2^645599823 is an apocalyptic number.

645599823 is a deficient number, since it is larger than the sum of its proper divisors (293454513).

645599823 is a wasteful number, since it uses less digits than its factorization.

645599823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19563645.

The product of its digits is 2332800, while the sum is 51.

The square root of 645599823 is about 25408.6564579869. The cubic root of 645599823 is about 864.2800085345.

The spelling of 645599823 in words is "six hundred forty-five million, five hundred ninety-nine thousand, eight hundred twenty-three".