87809779 has 2 divisors, whose sum is σ = 87809780. Its totient is φ = 87809778.

The previous prime is 87809753. The next prime is 87809833. The reversal of 87809779 is 97790878.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87809779 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (87809719) 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 as a sum of consecutive naturals, namely, 43904889 + 43904890.

It is an arithmetic number, because the mean of its divisors is an integer number (43904890).

Almost surely, 2^87809779 is an apocalyptic number.

87809779 is a deficient number, since it is larger than the sum of its proper divisors (1).

87809779 is an equidigital number, since it uses as much as digits as its factorization.

87809779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1778112, while the sum is 55.

The square root of 87809779 is about 9370.6872213301. The cubic root of 87809779 is about 444.4752962171.

It can be divided in two parts, 87809 and 779, that added together give a palindrome (88588).

The spelling of 87809779 in words is "eighty-seven million, eight hundred nine thousand, seven hundred seventy-nine".