21437443 has 2 divisors, whose sum is σ = 21437444. Its totient is φ = 21437442.

The previous prime is 21437441. The next prime is 21437501. The reversal of 21437443 is 34473412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21437443 - 2¹ = 21437441 is a prime.

Together with 21437441, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21437441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10718721 + 10718722.

It is an arithmetic number, because the mean of its divisors is an integer number (10718722).

Almost surely, 2^21437443 is an apocalyptic number.

21437443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21437443 is an equidigital number, since it uses as much as digits as its factorization.

21437443 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 28.

The square root of 21437443 is about 4630.0586389375. The cubic root of 21437443 is about 277.7949378851.

The spelling of 21437443 in words is "twenty-one million, four hundred thirty-seven thousand, four hundred forty-three".