82987891 has 4 divisors (see below), whose sum is σ = 94843312. Its totient is φ = 71132472.

The previous prime is 82987871. The next prime is 82987903. The reversal of 82987891 is 19878928.

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 82987891 - 2⁹ = 82987379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82987831) 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, 5927700 + ... + 5927713.

It is an arithmetic number, because the mean of its divisors is an integer number (23710828).

Almost surely, 2^82987891 is an apocalyptic number.

82987891 is a deficient number, since it is larger than the sum of its proper divisors (11855421).

82987891 is a wasteful number, since it uses less digits than its factorization.

82987891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11855420.

The product of its digits is 580608, while the sum is 52.

The square root of 82987891 is about 9109.7689871917. The cubic root of 82987891 is about 436.1858531364.

The spelling of 82987891 in words is "eighty-two million, nine hundred eighty-seven thousand, eight hundred ninety-one".