643678111 has 4 divisors (see below), whose sum is σ = 646440912. Its totient is φ = 640915312.

The previous prime is 643678109. The next prime is 643678121. The reversal of 643678111 is 111876346.

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 643678111 - 2¹ = 643678109 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 (643678121) 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, 1381051 + ... + 1381516.

It is an arithmetic number, because the mean of its divisors is an integer number (161610228).

Almost surely, 2^643678111 is an apocalyptic number.

643678111 is a deficient number, since it is larger than the sum of its proper divisors (2762801).

643678111 is a wasteful number, since it uses less digits than its factorization.

643678111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2762800.

The product of its digits is 24192, while the sum is 37.

The square root of 643678111 is about 25370.8121864476. The cubic root of 643678111 is about 863.4216089015.

The spelling of 643678111 in words is "six hundred forty-three million, six hundred seventy-eight thousand, one hundred eleven".