645973696923 has 4 divisors (see below), whose sum is σ = 861298262568. Its totient is φ = 430649131280.

The previous prime is 645973696873. The next prime is 645973696931. The reversal of 645973696923 is 329696379546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645973696923 - 2⁹ = 645973696411 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645973696523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107662282818 + ... + 107662282823.

It is an arithmetic number, because the mean of its divisors is an integer number (215324565642).

Almost surely, 2^645973696923 is an apocalyptic number.

645973696923 is a deficient number, since it is larger than the sum of its proper divisors (215324565645).

645973696923 is a wasteful number, since it uses less digits than its factorization.

645973696923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215324565644.

The product of its digits is 396809280, while the sum is 69.

The spelling of 645973696923 in words is "six hundred forty-five billion, nine hundred seventy-three million, six hundred ninety-six thousand, nine hundred twenty-three".