20391443 has 2 divisors, whose sum is σ = 20391444. Its totient is φ = 20391442.

The previous prime is 20391433. The next prime is 20391451. The reversal of 20391443 is 34419302.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20391443 - 2²⁴ = 3614227 is a prime.

It is not a weakly prime, because it can be changed into another prime (20391433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10195721 + 10195722.

It is an arithmetic number, because the mean of its divisors is an integer number (10195722).

Almost surely, 2^20391443 is an apocalyptic number.

20391443 is a deficient number, since it is larger than the sum of its proper divisors (1).

20391443 is an equidigital number, since it uses as much as digits as its factorization.

20391443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 20391443 is about 4515.6885410754. The cubic root of 20391443 is about 273.2012318563.

The spelling of 20391443 in words is "twenty million, three hundred ninety-one thousand, four hundred forty-three".