91008921 has 8 divisors (see below), whose sum is σ = 121487104. Its totient is φ = 60601680.

The previous prime is 91008913. The next prime is 91008943. The reversal of 91008921 is 12980019.

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

It is not a de Polignac number, because 91008921 - 2³ = 91008913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91008991) 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, 14665 + ... + 19926.

It is an arithmetic number, because the mean of its divisors is an integer number (15185888).

Almost surely, 2^91008921 is an apocalyptic number.

It is an amenable number.

91008921 is a deficient number, since it is larger than the sum of its proper divisors (30478183).

91008921 is a wasteful number, since it uses less digits than its factorization.

91008921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35471.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 91008921 is about 9539.8595901617. The cubic root of 91008921 is about 449.8088422654.

The spelling of 91008921 in words is "ninety-one million, eight thousand, nine hundred twenty-one".