91728407 has 2 divisors, whose sum is σ = 91728408. Its totient is φ = 91728406.

The previous prime is 91728391. The next prime is 91728419. The reversal of 91728407 is 70482719.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91728407 - 2⁴ = 91728391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91728457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45864203 + 45864204.

It is an arithmetic number, because the mean of its divisors is an integer number (45864204).

Almost surely, 2^91728407 is an apocalyptic number.

91728407 is a deficient number, since it is larger than the sum of its proper divisors (1).

91728407 is an equidigital number, since it uses as much as digits as its factorization.

91728407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 91728407 is about 9577.4948185838. The cubic root of 91728407 is about 450.9910782023.

The spelling of 91728407 in words is "ninety-one million, seven hundred twenty-eight thousand, four hundred seven".