91056821 has 8 divisors (see below), whose sum is σ = 91816320. Its totient is φ = 90300672.

The previous prime is 91056787. The next prime is 91056851. The reversal of 91056821 is 12865019.

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

It is a cyclic number.

It is not a de Polignac number, because 91056821 - 2¹⁸ = 90794677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91056851) 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, 88850 + ... + 89868.

It is an arithmetic number, because the mean of its divisors is an integer number (11477040).

Almost surely, 2^91056821 is an apocalyptic number.

It is an amenable number.

91056821 is a deficient number, since it is larger than the sum of its proper divisors (759499).

91056821 is a wasteful number, since it uses less digits than its factorization.

91056821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1675.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 91056821 is about 9542.3697790434. The cubic root of 91056821 is about 449.8877431922.

The spelling of 91056821 in words is "ninety-one million, fifty-six thousand, eight hundred twenty-one".