91728647 has 2 divisors, whose sum is σ = 91728648. Its totient is φ = 91728646.

The previous prime is 91728643. The next prime is 91728667. The reversal of 91728647 is 74682719.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91728647 - 2² = 91728643 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 91728598 and 91728607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91728641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45864323 + 45864324.

It is an arithmetic number, because the mean of its divisors is an integer number (45864324).

Almost surely, 2^91728647 is an apocalyptic number.

91728647 is a deficient number, since it is larger than the sum of its proper divisors (1).

91728647 is an equidigital number, since it uses as much as digits as its factorization.

91728647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 169344, while the sum is 44.

The square root of 91728647 is about 9577.5073479481. The cubic root of 91728647 is about 450.9914715293.

The spelling of 91728647 in words is "ninety-one million, seven hundred twenty-eight thousand, six hundred forty-seven".