641309 has 4 divisors (see below), whose sum is σ = 669216. Its totient is φ = 613404.

The previous prime is 641299. The next prime is 641317. The reversal of 641309 is 903146.

641309 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-641309 is a prime.

It is a super-2 number, since 2×641309² = 822554466962, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 27883 = 641309 / (6 + 4 + 1 + 3 + 0 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13919 + ... + 13964.

It is an arithmetic number, because the mean of its divisors is an integer number (167304).

2⁶⁴¹³⁰⁹ is an apocalyptic number.

It is an amenable number.

641309 is a deficient number, since it is larger than the sum of its proper divisors (27907).

641309 is a wasteful number, since it uses less digits than its factorization.

641309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27906.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 641309 is about 800.8177070969. The cubic root of 641309 is about 86.2361008198.

The spelling of 641309 in words is "six hundred forty-one thousand, three hundred nine".