91623121 has 2 divisors, whose sum is σ = 91623122. Its totient is φ = 91623120.

The previous prime is 91623113. The next prime is 91623131. The reversal of 91623121 is 12132619.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 86694721 + 4928400 = 9311^2 + 2220^2 .

It is an emirp because it is prime and its reverse (12132619) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91623121 - 2³ = 91623113 is a prime.

It is not a weakly prime, because it can be changed into another prime (91623131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45811560 + 45811561.

It is an arithmetic number, because the mean of its divisors is an integer number (45811561).

Almost surely, 2^91623121 is an apocalyptic number.

It is an amenable number.

91623121 is a deficient number, since it is larger than the sum of its proper divisors (1).

91623121 is an equidigital number, since it uses as much as digits as its factorization.

91623121 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 91623121 is about 9571.9967091511. The cubic root of 91623121 is about 450.8184627359.

The spelling of 91623121 in words is "ninety-one million, six hundred twenty-three thousand, one hundred twenty-one".