643652311 has 4 divisors (see below), whose sum is σ = 643740832. Its totient is φ = 643563792.

The previous prime is 643652221. The next prime is 643652323. The reversal of 643652311 is 113256346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643652311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643658311) 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, 32271 + ... + 48256.

It is an arithmetic number, because the mean of its divisors is an integer number (160935208).

Almost surely, 2^643652311 is an apocalyptic number.

643652311 is a deficient number, since it is larger than the sum of its proper divisors (88521).

643652311 is an equidigital number, since it uses as much as digits as its factorization.

643652311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88520.

The product of its digits is 12960, while the sum is 31.

The square root of 643652311 is about 25370.3037230538. The cubic root of 643652311 is about 863.4100728170.

The spelling of 643652311 in words is "six hundred forty-three million, six hundred fifty-two thousand, three hundred eleven".