91987390 has 32 divisors (see below), whose sum is σ = 183604320. Its totient is φ = 32899200.

The previous prime is 91987381. The next prime is 91987403. The reversal of 91987390 is 9378919.

It is a self number, because there is not a number n which added to its sum of digits gives 91987390.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 145 + ... + 13564.

It is an arithmetic number, because the mean of its divisors is an integer number (5737635).

Almost surely, 2^91987390 is an apocalyptic number.

91987390 is a deficient number, since it is larger than the sum of its proper divisors (91616930).

91987390 is a wasteful number, since it uses less digits than its factorization.

91987390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13788.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 91987390 is about 9591.0056824089. The cubic root of 91987390 is about 451.4151172255.

The spelling of 91987390 in words is "ninety-one million, nine hundred eighty-seven thousand, three hundred ninety".