645074 has 4 divisors (see below), whose sum is σ = 967614. Its totient is φ = 322536.

The previous prime is 645067. The next prime is 645077. The reversal of 645074 is 470546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 470546 = 2 ⋅235273.

It can be written as a sum of positive squares in only one way, i.e., 552049 + 93025 = 743^2 + 305^2 .

It is a super-2 number, since 2×645074² = 832240930952, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161267 + ... + 161270.

2⁶⁴⁵⁰⁷⁴ is an apocalyptic number.

645074 is a deficient number, since it is larger than the sum of its proper divisors (322540).

645074 is a wasteful number, since it uses less digits than its factorization.

645074 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322539.

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 645074 is about 803.1649892768. The cubic root of 645074 is about 86.4045300837.

The spelling of 645074 in words is "six hundred forty-five thousand, seventy-four".