643351 has 4 divisors (see below), whose sum is σ = 645472. Its totient is φ = 641232.

The previous prime is 643303. The next prime is 643369. The reversal of 643351 is 153346.

643351 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 an emirpimes, since its reverse is a distinct semiprime: 153346 = 2 ⋅76673.

It is a cyclic number.

It is not a de Polignac number, because 643351 - 2¹⁵ = 610583 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 (643301) 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, 510 + ... + 1243.

It is an arithmetic number, because the mean of its divisors is an integer number (161368).

2⁶⁴³³⁵¹ is an apocalyptic number.

643351 is a deficient number, since it is larger than the sum of its proper divisors (2121).

643351 is a wasteful number, since it uses less digits than its factorization.

643351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2120.

The product of its digits is 1080, while the sum is 22.

The square root of 643351 is about 802.0916406496. The cubic root of 643351 is about 86.3275323277.

Adding to 643351 its reverse (153346), we get a palindrome (796697).

The spelling of 643351 in words is "six hundred forty-three thousand, three hundred fifty-one".