91000172 has 12 divisors (see below), whose sum is σ = 159467616. Its totient is φ = 45438000.

The previous prime is 91000171. The next prime is 91000181. The reversal of 91000172 is 27100019.

It is not an unprimeable number, because it can be changed into a prime (91000171) 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, 12143 + ... + 18150.

It is an arithmetic number, because the mean of its divisors is an integer number (13288968).

Almost surely, 2^91000172 is an apocalyptic number.

It is an amenable number.

91000172 is a deficient number, since it is larger than the sum of its proper divisors (68467444).

91000172 is a wasteful number, since it uses less digits than its factorization.

91000172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31048 (or 31046 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 20.

The square root of 91000172 is about 9539.4010294148. The cubic root of 91000172 is about 449.7944279141.

It can be divided in two parts, 9100017 and 2, that added together give a palindrome (9100019).

The spelling of 91000172 in words is "ninety-one million, one hundred seventy-two", and thus it is an aban number.