643320355 has 8 divisors (see below), whose sum is σ = 774921312. Its totient is φ = 512698368.

The previous prime is 643320331. The next prime is 643320383. The reversal of 643320355 is 553023346.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643320355 is a prime.

It is a super-2 number, since 2×643320355² = 827722158314652050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243294 + ... + 245923.

It is an arithmetic number, because the mean of its divisors is an integer number (96865164).

Almost surely, 2^643320355 is an apocalyptic number.

643320355 is a deficient number, since it is larger than the sum of its proper divisors (131600957).

643320355 is a wasteful number, since it uses less digits than its factorization.

643320355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489485.

The product of its (nonzero) digits is 32400, while the sum is 31.

The square root of 643320355 is about 25363.7606635925. The cubic root of 643320355 is about 863.2616161446.

The spelling of 643320355 in words is "six hundred forty-three million, three hundred twenty thousand, three hundred fifty-five".