91079987 has 2 divisors, whose sum is σ = 91079988. Its totient is φ = 91079986.

The previous prime is 91079959. The next prime is 91080037. The reversal of 91079987 is 78997019.

It is an a-pointer prime, because the next prime (91080037) can be obtained adding 91079987 to its sum of digits (50).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91079987 - 2¹⁸ = 90817843 is a prime.

It is not a weakly prime, because it can be changed into another prime (91079587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45539993 + 45539994.

It is an arithmetic number, because the mean of its divisors is an integer number (45539994).

Almost surely, 2^91079987 is an apocalyptic number.

91079987 is a deficient number, since it is larger than the sum of its proper divisors (1).

91079987 is an equidigital number, since it uses as much as digits as its factorization.

91079987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 285768, while the sum is 50.

The square root of 91079987 is about 9543.5835512663. The cubic root of 91079987 is about 449.9258923231.

The spelling of 91079987 in words is "ninety-one million, seventy-nine thousand, nine hundred eighty-seven".