91999943 has 16 divisors (see below), whose sum is σ = 106659840. Its totient is φ = 77728896.

The previous prime is 91999907. The next prime is 91999951. The reversal of 91999943 is 34999919.

It is not a de Polignac number, because 91999943 - 2⁶ = 91999879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91999993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 212255 + ... + 212687.

It is an arithmetic number, because the mean of its divisors is an integer number (6666240).

Almost surely, 2^91999943 is an apocalyptic number.

91999943 is a deficient number, since it is larger than the sum of its proper divisors (14659897).

91999943 is a wasteful number, since it uses less digits than its factorization.

91999943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 806.

The product of its digits is 708588, while the sum is 53.

The square root of 91999943 is about 9591.6600752946. The cubic root of 91999943 is about 451.4356503161.

The spelling of 91999943 in words is "ninety-one million, nine hundred ninety-nine thousand, nine hundred forty-three".