643140091 has 4 divisors (see below), whose sum is σ = 701607384. Its totient is φ = 584672800.

The previous prime is 643140079. The next prime is 643140097. The reversal of 643140091 is 190041346.

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

It is a cyclic number.

It is not a de Polignac number, because 643140091 - 2⁵ = 643140059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643140097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29233630 + ... + 29233651.

It is an arithmetic number, because the mean of its divisors is an integer number (175401846).

Almost surely, 2^643140091 is an apocalyptic number.

643140091 is a deficient number, since it is larger than the sum of its proper divisors (58467293).

643140091 is a wasteful number, since it uses less digits than its factorization.

643140091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58467292.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 643140091 is about 25360.2068406391. The cubic root of 643140091 is about 863.1809774561.

It can be divided in two parts, 6431400 and 91, that added together give a triangular number (6431491 = T₃₅₈₆).

The spelling of 643140091 in words is "six hundred forty-three million, one hundred forty thousand, ninety-one".