645689692 has 24 divisors (see below), whose sum is σ = 1193225040. Its totient is φ = 304876800.

The previous prime is 645689683. The next prime is 645689729. The reversal of 645689692 is 296986546.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10692 + ... + 37492.

It is an arithmetic number, because the mean of its divisors is an integer number (49717710).

Almost surely, 2^645689692 is an apocalyptic number.

It is an amenable number.

645689692 is a deficient number, since it is larger than the sum of its proper divisors (547535348).

645689692 is a wasteful number, since it uses less digits than its factorization.

645689692 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27141 (or 27139 counting only the distinct ones).

The product of its digits is 5598720, while the sum is 55.

The square root of 645689692 is about 25410.4248685456. The cubic root of 645689692 is about 864.3201099376.

The spelling of 645689692 in words is "six hundred forty-five million, six hundred eighty-nine thousand, six hundred ninety-two".