91009787 has 16 divisors (see below), whose sum is σ = 101244384. Its totient is φ = 81796000.

The previous prime is 91009771. The next prime is 91009799. The reversal of 91009787 is 78790019.

It is not a de Polignac number, because 91009787 - 2⁴ = 91009771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91009727) 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 in 15 ways as a sum of consecutive naturals, for example, 134093 + ... + 134769.

It is an arithmetic number, because the mean of its divisors is an integer number (6327774).

Almost surely, 2^91009787 is an apocalyptic number.

91009787 is a deficient number, since it is larger than the sum of its proper divisors (10234597).

91009787 is a wasteful number, since it uses less digits than its factorization.

91009787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 811 (or 789 counting only the distinct ones).

The product of its (nonzero) digits is 31752, while the sum is 41.

The square root of 91009787 is about 9539.9049785624. The cubic root of 91009787 is about 449.8102689872.

The spelling of 91009787 in words is "ninety-one million, nine thousand, seven hundred eighty-seven".