91121623 has 2 divisors, whose sum is σ = 91121624. Its totient is φ = 91121622.

The previous prime is 91121621. The next prime is 91121629. The reversal of 91121623 is 32612119.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91121623 - 2¹ = 91121621 is a prime.

Together with 91121621, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91121621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45560811 + 45560812.

It is an arithmetic number, because the mean of its divisors is an integer number (45560812).

Almost surely, 2^91121623 is an apocalyptic number.

91121623 is a deficient number, since it is larger than the sum of its proper divisors (1).

91121623 is an equidigital number, since it uses as much as digits as its factorization.

91121623 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 91121623 is about 9545.7646629277. The cubic root of 91121623 is about 449.9944410836.

The spelling of 91121623 in words is "ninety-one million, one hundred twenty-one thousand, six hundred twenty-three".