91911021 has 8 divisors (see below), whose sum is σ = 122913024. Its totient is φ = 61091520.

The previous prime is 91911007. The next prime is 91911047. The reversal of 91911021 is 12011919.

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

It is not a de Polignac number, because 91911021 - 2⁹ = 91910509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 91910982 and 91911000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91911221) 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 in 7 ways as a sum of consecutive naturals, for example, 44445 + ... + 46466.

It is an arithmetic number, because the mean of its divisors is an integer number (15364128).

Almost surely, 2^91911021 is an apocalyptic number.

It is an amenable number.

91911021 is a deficient number, since it is larger than the sum of its proper divisors (31002003).

91911021 is a wasteful number, since it uses less digits than its factorization.

91911021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91251.

The product of its (nonzero) digits is 162, while the sum is 24.

The square root of 91911021 is about 9587.0235735603. The cubic root of 91911021 is about 451.2901592802.

The spelling of 91911021 in words is "ninety-one million, nine hundred eleven thousand, twenty-one".