91987970 has 16 divisors (see below), whose sum is σ = 165689280. Its totient is φ = 36770544.

The previous prime is 91987963. The next prime is 91987979. The reversal of 91987970 is 7978919.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91987979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23579 + ... + 27201.

It is an arithmetic number, because the mean of its divisors is an integer number (10355580).

Almost surely, 2^91987970 is an apocalyptic number.

91987970 is a deficient number, since it is larger than the sum of its proper divisors (73701310).

91987970 is a wasteful number, since it uses less digits than its factorization.

91987970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6169.

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

The square root of 91987970 is about 9591.0359190236. The cubic root of 91987970 is about 451.4160659796.

The spelling of 91987970 in words is "ninety-one million, nine hundred eighty-seven thousand, nine hundred seventy".