82099991 has 4 divisors (see below), whose sum is σ = 83325432. Its totient is φ = 80874552.

The previous prime is 82099973. The next prime is 82100009. The reversal of 82099991 is 19999028.

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

It is an interprime number because it is at equal distance from previous prime (82099973) and next prime (82100009).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82099991 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 (82099891) 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, 612620 + ... + 612753.

It is an arithmetic number, because the mean of its divisors is an integer number (20831358).

Almost surely, 2^82099991 is an apocalyptic number.

82099991 is a deficient number, since it is larger than the sum of its proper divisors (1225441).

82099991 is a wasteful number, since it uses less digits than its factorization.

82099991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1225440.

The product of its (nonzero) digits is 104976, while the sum is 47.

The square root of 82099991 is about 9060.9045354203. The cubic root of 82099991 is about 434.6246658917.

The spelling of 82099991 in words is "eighty-two million, ninety-nine thousand, nine hundred ninety-one".