645798 has 16 divisors (see below), whose sum is σ = 1326960. Its totient is φ = 209376.

The previous prime is 645787. The next prime is 645803. The reversal of 645798 is 897546.

It is a nialpdrome in base 15.

It is a congruent number.

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, 1233 + ... + 1676.

It is an arithmetic number, because the mean of its divisors is an integer number (82935).

2⁶⁴⁵⁷⁹⁸ is an apocalyptic number.

645798 is an abundant number, since it is smaller than the sum of its proper divisors (681162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645798 is a wasteful number, since it uses less digits than its factorization.

645798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2951.

The product of its digits is 60480, while the sum is 39.

The square root of 645798 is about 803.6155797395. The cubic root of 645798 is about 86.4368434259.

It can be divided in two parts, 6457 and 98, that added together give a triangular number (6555 = T₁₁₄).

The spelling of 645798 in words is "six hundred forty-five thousand, seven hundred ninety-eight".