645266 has 4 divisors (see below), whose sum is σ = 967902. Its totient is φ = 322632.

The previous prime is 645257. The next prime is 645313. The reversal of 645266 is 662546.

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

It can be written as a sum of positive squares in only one way, i.e., 326041 + 319225 = 571^2 + 565^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161315 + ... + 161318.

2⁶⁴⁵²⁶⁶ is an apocalyptic number.

645266 is a deficient number, since it is larger than the sum of its proper divisors (322636).

645266 is a wasteful number, since it uses less digits than its factorization.

645266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322635.

The product of its digits is 8640, while the sum is 29.

The square root of 645266 is about 803.2845075065. The cubic root of 645266 is about 86.4131017226.

The spelling of 645266 in words is "six hundred forty-five thousand, two hundred sixty-six".