21446081 has 2 divisors, whose sum is σ = 21446082. Its totient is φ = 21446080.

The previous prime is 21446071. The next prime is 21446083. The reversal of 21446081 is 18064412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17505856 + 3940225 = 4184^2 + 1985^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21446081 is a prime.

It is a super-2 number, since 2×21446081² = 919868780517122, which contains 22 as substring.

Together with 21446083, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21446081.

It is not a weakly prime, because it can be changed into another prime (21446083) 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, 10723040 + 10723041.

It is an arithmetic number, because the mean of its divisors is an integer number (10723041).

Almost surely, 2^21446081 is an apocalyptic number.

It is an amenable number.

21446081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21446081 is an equidigital number, since it uses as much as digits as its factorization.

21446081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21446081 is about 4630.9913625486. The cubic root of 21446081 is about 277.8322444247.

The spelling of 21446081 in words is "twenty-one million, four hundred forty-six thousand, eighty-one".