82780091 has 4 divisors (see below), whose sum is σ = 83633592. Its totient is φ = 81926592.

The previous prime is 82780081. The next prime is 82780097. The reversal of 82780091 is 19008728.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82780091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82780097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 426605 + ... + 426798.

It is an arithmetic number, because the mean of its divisors is an integer number (20908398).

Almost surely, 2^82780091 is an apocalyptic number.

82780091 is a deficient number, since it is larger than the sum of its proper divisors (853501).

82780091 is an equidigital number, since it uses as much as digits as its factorization.

82780091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853500.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 82780091 is about 9098.3564999400. The cubic root of 82780091 is about 435.8214819906.

The spelling of 82780091 in words is "eighty-two million, seven hundred eighty thousand, ninety-one".