643397 has 4 divisors (see below), whose sum is σ = 677280. Its totient is φ = 609516.

The previous prime is 643373. The next prime is 643403. The reversal of 643397 is 793346.

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 not a de Polignac number, because 643397 - 2¹⁰ = 642373 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643697) 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, 16913 + ... + 16950.

It is an arithmetic number, because the mean of its divisors is an integer number (169320).

2⁶⁴³³⁹⁷ is an apocalyptic number.

It is an amenable number.

643397 is a deficient number, since it is larger than the sum of its proper divisors (33883).

643397 is a wasteful number, since it uses less digits than its factorization.

643397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33882.

The product of its digits is 13608, while the sum is 32.

The square root of 643397 is about 802.1203151648. The cubic root of 643397 is about 86.3295897696.

It can be divided in two parts, 64339 and 7, that added together give a palindrome (64346).

The spelling of 643397 in words is "six hundred forty-three thousand, three hundred ninety-seven".