91121213 has 2 divisors, whose sum is σ = 91121214. Its totient is φ = 91121212.

The previous prime is 91121209. The next prime is 91121227. The reversal of 91121213 is 31212119.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83868964 + 7252249 = 9158^2 + 2693^2 .

It is a cyclic number.

It is not a de Polignac number, because 91121213 - 2² = 91121209 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91121243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45560606 + 45560607.

It is an arithmetic number, because the mean of its divisors is an integer number (45560607).

Almost surely, 2^91121213 is an apocalyptic number.

It is an amenable number.

91121213 is a deficient number, since it is larger than the sum of its proper divisors (1).

91121213 is an equidigital number, since it uses as much as digits as its factorization.

91121213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 20.

The square root of 91121213 is about 9545.7431874108. The cubic root of 91121213 is about 449.9937661688.

The spelling of 91121213 in words is "ninety-one million, one hundred twenty-one thousand, two hundred thirteen".