20405443 has 2 divisors, whose sum is σ = 20405444. Its totient is φ = 20405442.

The previous prime is 20405387. The next prime is 20405459. The reversal of 20405443 is 34450402.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20405443 - 2²¹ = 18308291 is a prime.

It is not a weakly prime, because it can be changed into another prime (20405743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10202721 + 10202722.

It is an arithmetic number, because the mean of its divisors is an integer number (10202722).

Almost surely, 2^20405443 is an apocalyptic number.

20405443 is a deficient number, since it is larger than the sum of its proper divisors (1).

20405443 is an equidigital number, since it uses as much as digits as its factorization.

20405443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1920, while the sum is 22.

The square root of 20405443 is about 4517.2384262954. The cubic root of 20405443 is about 273.2637407929.

Adding to 20405443 its reverse (34450402), we get a palindrome (54855845).

The spelling of 20405443 in words is "twenty million, four hundred five thousand, four hundred forty-three".