91399787 has 4 divisors (see below), whose sum is σ = 91603800. Its totient is φ = 91195776.

The previous prime is 91399753. The next prime is 91399843. The reversal of 91399787 is 78799319.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78799319 = 619 ⋅127301.

It is a cyclic number.

It is not a de Polignac number, because 91399787 - 2¹⁰ = 91398763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91399717) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101333 + ... + 102230.

It is an arithmetic number, because the mean of its divisors is an integer number (22900950).

Almost surely, 2^91399787 is an apocalyptic number.

91399787 is a deficient number, since it is larger than the sum of its proper divisors (204013).

91399787 is a wasteful number, since it uses less digits than its factorization.

91399787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204012.

The product of its digits is 857304, while the sum is 53.

The square root of 91399787 is about 9560.3235823899. The cubic root of 91399787 is about 450.4518703794.

The spelling of 91399787 in words is "ninety-one million, three hundred ninety-nine thousand, seven hundred eighty-seven".