43221391 has 2 divisors, whose sum is σ = 43221392. Its totient is φ = 43221390.

The previous prime is 43221383. The next prime is 43221403. The reversal of 43221391 is 19312234.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 43221391 - 2³ = 43221383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43221331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21610695 + 21610696.

It is an arithmetic number, because the mean of its divisors is an integer number (21610696).

Almost surely, 2^43221391 is an apocalyptic number.

43221391 is a deficient number, since it is larger than the sum of its proper divisors (1).

43221391 is an equidigital number, since it uses as much as digits as its factorization.

43221391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 25.

The square root of 43221391 is about 6574.2977571753. The cubic root of 43221391 is about 350.9400335323.

The spelling of 43221391 in words is "forty-three million, two hundred twenty-one thousand, three hundred ninety-one".