645418 has 4 divisors (see below), whose sum is σ = 968130. Its totient is φ = 322708.

The previous prime is 645409. The next prime is 645419. The reversal of 645418 is 814546.

645418 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 814546 = 2 ⋅407273.

It can be written as a sum of positive squares in only one way, i.e., 466489 + 178929 = 683^2 + 423^2 .

It is not an unprimeable number, because it can be changed into a prime (645419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161353 + ... + 161356.

2⁶⁴⁵⁴¹⁸ is an apocalyptic number.

645418 is a deficient number, since it is larger than the sum of its proper divisors (322712).

645418 is a wasteful number, since it uses less digits than its factorization.

645418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322711.

The product of its digits is 3840, while the sum is 28.

The square root of 645418 is about 803.3791134950. The cubic root of 645418 is about 86.4198863975.

The spelling of 645418 in words is "six hundred forty-five thousand, four hundred eighteen".