91606921 has 6 divisors (see below), whose sum is σ = 106563210. Its totient is φ = 78520176.

The previous prime is 91606903. The next prime is 91606937. The reversal of 91606921 is 12960619.

It can be written as a sum of positive squares in only one way, i.e., 61795321 + 29811600 = 7861^2 + 5460^2 .

It is not a de Polignac number, because 91606921 - 2¹¹ = 91604873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91606321) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 934716 + ... + 934813.

It is an arithmetic number, because the mean of its divisors is an integer number (17760535).

Almost surely, 2^91606921 is an apocalyptic number.

It is an amenable number.

91606921 is a deficient number, since it is larger than the sum of its proper divisors (14956289).

91606921 is a wasteful number, since it uses less digits than its factorization.

91606921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1869543 (or 1869536 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 91606921 is about 9571.1504533154. The cubic root of 91606921 is about 450.7918912421.

The spelling of 91606921 in words is "ninety-one million, six hundred six thousand, nine hundred twenty-one".