21231841 has 2 divisors, whose sum is σ = 21231842. Its totient is φ = 21231840.

The previous prime is 21231823. The next prime is 21231851. The reversal of 21231841 is 14813212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16842816 + 4389025 = 4104^2 + 2095^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231841 - 2⁷ = 21231713 is a prime.

It is not a weakly prime, because it can be changed into another prime (21231811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615920 + 10615921.

It is an arithmetic number, because the mean of its divisors is an integer number (10615921).

Almost surely, 2^21231841 is an apocalyptic number.

It is an amenable number.

21231841 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231841 is an equidigital number, since it uses as much as digits as its factorization.

21231841 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 22.

The square root of 21231841 is about 4607.8021875944. The cubic root of 21231841 is about 276.9039925852.

The spelling of 21231841 in words is "twenty-one million, two hundred thirty-one thousand, eight hundred forty-one".