7491221 has 2 divisors, whose sum is σ = 7491222. Its totient is φ = 7491220.

The previous prime is 7491217. The next prime is 7491223. The reversal of 7491221 is 1221947.

7491221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6180196 + 1311025 = 2486^2 + 1145^2 .

It is a cyclic number.

It is not a de Polignac number, because 7491221 - 2² = 7491217 is a prime.

It is a super-2 number, since 2×7491221² = 112236784141682, which contains 22 as substring.

Together with 7491223, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7491223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3745610 + 3745611.

It is an arithmetic number, because the mean of its divisors is an integer number (3745611).

Almost surely, 2^7491221 is an apocalyptic number.

It is an amenable number.

7491221 is a deficient number, since it is larger than the sum of its proper divisors (1).

7491221 is an equidigital number, since it uses as much as digits as its factorization.

7491221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 26.

The square root of 7491221 is about 2737.0094994355. The cubic root of 7491221 is about 195.6669775215. Note that the first 3 decimals are identical.

The spelling of 7491221 in words is "seven million, four hundred ninety-one thousand, two hundred twenty-one".