645574 has 8 divisors (see below), whose sum is σ = 980280. Its totient is φ = 318816.

The previous prime is 645571. The next prime is 645577. The reversal of 645574 is 475546.

645574 = T₃₂₂ + T₃₂₃ + ... + T₃₃₃.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (645571) and next prime (645577).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1779 + ... + 2110.

It is an arithmetic number, because the mean of its divisors is an integer number (122535).

2⁶⁴⁵⁵⁷⁴ is an apocalyptic number.

645574 is a deficient number, since it is larger than the sum of its proper divisors (334706).

645574 is a wasteful number, since it uses less digits than its factorization.

645574 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3974.

The product of its digits is 16800, while the sum is 31.

The square root of 645574 is about 803.4761975317. The cubic root of 645574 is about 86.4268485090.

It can be divided in two parts, 645 and 574, that multiplied together give a triangular number (370230 = T₈₆₀).

The spelling of 645574 in words is "six hundred forty-five thousand, five hundred seventy-four".