645554 has 16 divisors (see below), whose sum is σ = 1192128. Its totient is φ = 255312.

The previous prime is 645529. The next prime is 645571. The reversal of 645554 is 455546.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1592 + ... + 1955.

It is an arithmetic number, because the mean of its divisors is an integer number (74508).

2⁶⁴⁵⁵⁵⁴ is an apocalyptic number.

645554 is a deficient number, since it is larger than the sum of its proper divisors (546574).

645554 is a wasteful number, since it uses less digits than its factorization.

645554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3569.

The product of its digits is 12000, while the sum is 29.

The square root of 645554 is about 803.4637515159. The cubic root of 645554 is about 86.4259559933.

The spelling of 645554 in words is "six hundred forty-five thousand, five hundred fifty-four".