645169 has 16 divisors (see below), whose sum is σ = 787968. Its totient is φ = 516672.

The previous prime is 645149. The next prime is 645179. The reversal of 645169 is 961546.

It is a cyclic number.

It is not a de Polignac number, because 645169 - 2⁵ = 645137 is a prime.

It is a super-2 number, since 2×645169² = 832486077122, which contains 22 as substring.

It is a Duffinian number.

Its product of digits (6480) is a multiple of the sum of its prime divisors (144).

It is a self number, because there is not a number n which added to its sum of digits gives 645169.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645149) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12147 + ... + 12199.

It is an arithmetic number, because the mean of its divisors is an integer number (49248).

2⁶⁴⁵¹⁶⁹ is an apocalyptic number.

It is an amenable number.

645169 is a deficient number, since it is larger than the sum of its proper divisors (142799).

645169 is a wasteful number, since it uses less digits than its factorization.

645169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144.

The product of its digits is 6480, while the sum is 31.

The square root of 645169 is about 803.2241281237. The cubic root of 645169 is about 86.4087714717.

It can be divided in two parts, 64516 and 9, that multiplied together give a square (580644 = 762²).

The spelling of 645169 in words is "six hundred forty-five thousand, one hundred sixty-nine".