91066621 has 2 divisors, whose sum is σ = 91066622. Its totient is φ = 91066620.

The previous prime is 91066609. The next prime is 91066627. The reversal of 91066621 is 12666019.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73719396 + 17347225 = 8586^2 + 4165^2 .

It is an emirp because it is prime and its reverse (12666019) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91066621 - 2⁹ = 91066109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91066627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45533310 + 45533311.

It is an arithmetic number, because the mean of its divisors is an integer number (45533311).

Almost surely, 2^91066621 is an apocalyptic number.

It is an amenable number.

91066621 is a deficient number, since it is larger than the sum of its proper divisors (1).

91066621 is an equidigital number, since it uses as much as digits as its factorization.

91066621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 91066621 is about 9542.8832645066. The cubic root of 91066621 is about 449.9038823519.

The spelling of 91066621 in words is "ninety-one million, sixty-six thousand, six hundred twenty-one".