91787197 has 2 divisors, whose sum is σ = 91787198. Its totient is φ = 91787196.

The previous prime is 91787191. The next prime is 91787203. The reversal of 91787197 is 79178719.

It is a balanced prime because it is at equal distance from previous prime (91787191) and next prime (91787203).

It can be written as a sum of positive squares in only one way, i.e., 78747876 + 13039321 = 8874^2 + 3611^2 .

It is a cyclic number.

It is not a de Polignac number, because 91787197 - 2²³ = 83398589 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91787197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91787191) 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 as a sum of consecutive naturals, namely, 45893598 + 45893599.

It is an arithmetic number, because the mean of its divisors is an integer number (45893599).

Almost surely, 2^91787197 is an apocalyptic number.

It is an amenable number.

91787197 is a deficient number, since it is larger than the sum of its proper divisors (1).

91787197 is an equidigital number, since it uses as much as digits as its factorization.

91787197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 222264, while the sum is 49.

The square root of 91787197 is about 9580.5635011726. The cubic root of 91787197 is about 451.0874064247.

The spelling of 91787197 in words is "ninety-one million, seven hundred eighty-seven thousand, one hundred ninety-seven".