21241819 has 2 divisors, whose sum is σ = 21241820. Its totient is φ = 21241818.

The previous prime is 21241799. The next prime is 21241837. The reversal of 21241819 is 91814212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21241819 - 2¹³ = 21233627 is a prime.

It is a super-2 number, since 2×21241819² = 902429748857522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21241849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620909 + 10620910.

It is an arithmetic number, because the mean of its divisors is an integer number (10620910).

Almost surely, 2^21241819 is an apocalyptic number.

21241819 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241819 is an equidigital number, since it uses as much as digits as its factorization.

21241819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 28.

The square root of 21241819 is about 4608.8847891871. The cubic root of 21241819 is about 276.9473632210.

The spelling of 21241819 in words is "twenty-one million, two hundred forty-one thousand, eight hundred nineteen".