9091921 has 2 divisors, whose sum is σ = 9091922. Its totient is φ = 9091920.

The previous prime is 9091909. The next prime is 9091939. The reversal of 9091921 is 1291909.

9091921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7349521 + 1742400 = 2711^2 + 1320^2 .

It is an emirp because it is prime and its reverse (1291909) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9091921 - 2¹⁵ = 9059153 is a prime.

9091921 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (9091961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4545960 + 4545961.

It is an arithmetic number, because the mean of its divisors is an integer number (4545961).

Almost surely, 2^9091921 is an apocalyptic number.

It is an amenable number.

9091921 is a deficient number, since it is larger than the sum of its proper divisors (1).

9091921 is an equidigital number, since it uses as much as digits as its factorization.

9091921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 9091921 is about 3015.2812472471. The cubic root of 9091921 is about 208.7141456582.

The spelling of 9091921 in words is "nine million, ninety-one thousand, nine hundred twenty-one".