91421709 has 8 divisors (see below), whose sum is σ = 125190240. Its totient is φ = 59300496.

The previous prime is 91421689. The next prime is 91421713. The reversal of 91421709 is 90712419.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 91421709 - 2⁷ = 91421581 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91421709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91421719) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 411699 + ... + 411920.

It is an arithmetic number, because the mean of its divisors is an integer number (15648780).

Almost surely, 2^91421709 is an apocalyptic number.

It is an amenable number.

91421709 is a deficient number, since it is larger than the sum of its proper divisors (33768531).

91421709 is a wasteful number, since it uses less digits than its factorization.

91421709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 823659.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 91421709 is about 9561.4700229620. The cubic root of 91421709 is about 450.4878807351.

The spelling of 91421709 in words is "ninety-one million, four hundred twenty-one thousand, seven hundred nine".