21482581 has 2 divisors, whose sum is σ = 21482582. Its totient is φ = 21482580.

The previous prime is 21482567. The next prime is 21482603. The reversal of 21482581 is 18528412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16329681 + 5152900 = 4041^2 + 2270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21482581 - 2¹⁷ = 21351509 is a prime.

It is a super-2 number, since 2×21482581² = 923002572843122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21482081) 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, 10741290 + 10741291.

It is an arithmetic number, because the mean of its divisors is an integer number (10741291).

Almost surely, 2^21482581 is an apocalyptic number.

It is an amenable number.

21482581 is a deficient number, since it is larger than the sum of its proper divisors (1).

21482581 is an equidigital number, since it uses as much as digits as its factorization.

21482581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5120, while the sum is 31.

The square root of 21482581 is about 4634.9305280662. The cubic root of 21482581 is about 277.9897732725.

The spelling of 21482581 in words is "twenty-one million, four hundred eighty-two thousand, five hundred eighty-one".