21541447 has 2 divisors, whose sum is σ = 21541448. Its totient is φ = 21541446.

The previous prime is 21541439. The next prime is 21541451. The reversal of 21541447 is 74414512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21541447 - 2³ = 21541439 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21541417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770723 + 10770724.

It is an arithmetic number, because the mean of its divisors is an integer number (10770724).

Almost surely, 2^21541447 is an apocalyptic number.

21541447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21541447 is an equidigital number, since it uses as much as digits as its factorization.

21541447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4480, while the sum is 28.

The square root of 21541447 is about 4641.2764408081. The cubic root of 21541447 is about 278.2434551096.

Adding to 21541447 its reverse (74414512), we get a palindrome (95955959).

The spelling of 21541447 in words is "twenty-one million, five hundred forty-one thousand, four hundred forty-seven".