91423621 has 2 divisors, whose sum is σ = 91423622. Its totient is φ = 91423620.

The previous prime is 91423613. The next prime is 91423639. The reversal of 91423621 is 12632419.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80460900 + 10962721 = 8970^2 + 3311^2 .

It is a cyclic number.

It is not a de Polignac number, because 91423621 - 2³ = 91423613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91423621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91423021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45711810 + 45711811.

It is an arithmetic number, because the mean of its divisors is an integer number (45711811).

Almost surely, 2^91423621 is an apocalyptic number.

It is an amenable number.

91423621 is a deficient number, since it is larger than the sum of its proper divisors (1).

91423621 is an equidigital number, since it uses as much as digits as its factorization.

91423621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 28.

The square root of 91423621 is about 9561.5700070647. The cubic root of 91423621 is about 450.4910212249.

The spelling of 91423621 in words is "ninety-one million, four hundred twenty-three thousand, six hundred twenty-one".