91872173 has 2 divisors, whose sum is σ = 91872174. Its totient is φ = 91872172.

The previous prime is 91872113. The next prime is 91872197. The reversal of 91872173 is 37127819.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77757124 + 14115049 = 8818^2 + 3757^2 .

It is a cyclic number.

It is not a de Polignac number, because 91872173 - 2¹⁰ = 91871149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91872113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45936086 + 45936087.

It is an arithmetic number, because the mean of its divisors is an integer number (45936087).

Almost surely, 2^91872173 is an apocalyptic number.

It is an amenable number.

91872173 is a deficient number, since it is larger than the sum of its proper divisors (1).

91872173 is an equidigital number, since it uses as much as digits as its factorization.

91872173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 38.

The square root of 91872173 is about 9584.9972874279. The cubic root of 91872173 is about 451.2265681006.

The spelling of 91872173 in words is "ninety-one million, eight hundred seventy-two thousand, one hundred seventy-three".