645790 has 8 divisors (see below), whose sum is σ = 1162440. Its totient is φ = 258312.

The previous prime is 645787. The next prime is 645803. The reversal of 645790 is 97546.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32280 + ... + 32299.

It is an arithmetic number, because the mean of its divisors is an integer number (145305).

2⁶⁴⁵⁷⁹⁰ is an apocalyptic number.

645790 is a deficient number, since it is larger than the sum of its proper divisors (516650).

645790 is a wasteful number, since it uses less digits than its factorization.

645790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64586.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 645790 is about 803.6106022198. The cubic root of 645790 is about 86.4364865044.

It can be divided in two parts, 6 and 45790, that added together give a square (45796 = 214²).

The spelling of 645790 in words is "six hundred forty-five thousand, seven hundred ninety".