643172311 has 2 divisors, whose sum is σ = 643172312. Its totient is φ = 643172310.

The previous prime is 643172303. The next prime is 643172317. The reversal of 643172311 is 113271346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643172311 - 2³ = 643172303 is a prime.

It is a super-3 number, since 3×643172311³ (a number of 27 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 643172311.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643172317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321586155 + 321586156.

It is an arithmetic number, because the mean of its divisors is an integer number (321586156).

Almost surely, 2^643172311 is an apocalyptic number.

643172311 is a deficient number, since it is larger than the sum of its proper divisors (1).

643172311 is an equidigital number, since it uses as much as digits as its factorization.

643172311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 28.

The square root of 643172311 is about 25360.8420798679. The cubic root of 643172311 is about 863.1953917478.

The spelling of 643172311 in words is "six hundred forty-three million, one hundred seventy-two thousand, three hundred eleven".