641645 has 8 divisors (see below), whose sum is σ = 775320. Its totient is φ = 509760.

The previous prime is 641639. The next prime is 641681. The reversal of 641645 is 546146.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 31684 + 609961 = 178^2 + 781^2 .

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

It is not a de Polignac number, because 641645 - 2⁶ = 641581 is a prime.

It is a super-3 number, since 3×641645³ = 792511728058233375, which contains 333 as substring.

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, 551 + ... + 1259.

It is an arithmetic number, because the mean of its divisors is an integer number (96915).

2⁶⁴¹⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

641645 is a deficient number, since it is larger than the sum of its proper divisors (133675).

641645 is a wasteful number, since it uses less digits than its factorization.

641645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 895.

The product of its digits is 2880, while the sum is 26.

The square root of 641645 is about 801.0274651970. The cubic root of 641645 is about 86.2511587046.

The spelling of 641645 in words is "six hundred forty-one thousand, six hundred forty-five".