87815779 has 2 divisors, whose sum is σ = 87815780. Its totient is φ = 87815778.

The previous prime is 87815773. The next prime is 87815807. The reversal of 87815779 is 97751878.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 87815779 - 2⁹ = 87815267 is a prime.

It is a super-2 number, since 2×87815779² = 15423222082753682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (87815773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43907889 + 43907890.

It is an arithmetic number, because the mean of its divisors is an integer number (43907890).

Almost surely, 2^87815779 is an apocalyptic number.

87815779 is a deficient number, since it is larger than the sum of its proper divisors (1).

87815779 is an equidigital number, since it uses as much as digits as its factorization.

87815779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 987840, while the sum is 52.

The square root of 87815779 is about 9371.0073631387. The cubic root of 87815779 is about 444.4854195810.

The spelling of 87815779 in words is "eighty-seven million, eight hundred fifteen thousand, seven hundred seventy-nine".