99985591 has 16 divisors (see below), whose sum is σ = 106761600. Its totient is φ = 93477888.

The previous prime is 99985579. The next prime is 99985603. The reversal of 99985591 is 19558999.

It is an interprime number because it is at equal distance from previous prime (99985579) and next prime (99985603).

It is a cyclic number.

It is not a de Polignac number, because 99985591 - 2⁵ = 99985559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99985091) 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, 148231 + ... + 148903.

It is an arithmetic number, because the mean of its divisors is an integer number (6672600).

Almost surely, 2^99985591 is an apocalyptic number.

99985591 is a deficient number, since it is larger than the sum of its proper divisors (6776009).

99985591 is a wasteful number, since it uses less digits than its factorization.

99985591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 858.

The product of its digits is 1312200, while the sum is 55.

The square root of 99985591 is about 9999.2795240457. The cubic root of 99985591 is about 464.1365887393.

It can be divided in two parts, 99985 and 591, that added together give a triangular number (100576 = T₄₄₈).

The spelling of 99985591 in words is "ninety-nine million, nine hundred eighty-five thousand, five hundred ninety-one".