91985643 has 12 divisors (see below), whose sum is σ = 135958680. Its totient is φ = 59897376.

The previous prime is 91985639. The next prime is 91985693. The reversal of 91985643 is 34658919.

It is a happy number.

It is not a de Polignac number, because 91985643 - 2² = 91985639 is a prime.

It is a super-2 number, since 2×91985643² = 16922717036246898, which contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (91985633) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 118458 + ... + 119231.

It is an arithmetic number, because the mean of its divisors is an integer number (11329890).

Almost surely, 2^91985643 is an apocalyptic number.

91985643 is a deficient number, since it is larger than the sum of its proper divisors (43973037).

91985643 is a wasteful number, since it uses less digits than its factorization.

91985643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237738 (or 237735 counting only the distinct ones).

The product of its digits is 233280, while the sum is 45.

The square root of 91985643 is about 9590.9146070643. The cubic root of 91985643 is about 451.4122594889.

It can be divided in two parts, 9198 and 5643, that added together give a palindrome (14841).

The spelling of 91985643 in words is "ninety-one million, nine hundred eighty-five thousand, six hundred forty-three".