21401089 has 2 divisors, whose sum is σ = 21401090. Its totient is φ = 21401088.

The previous prime is 21401071. The next prime is 21401111. The reversal of 21401089 is 98010412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19210689 + 2190400 = 4383^2 + 1480^2 .

It is a cyclic number.

It is not a de Polignac number, because 21401089 - 2¹¹ = 21399041 is a prime.

It is a super-2 number, since 2×21401089² = 916013220771842, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21401069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700544 + 10700545.

It is an arithmetic number, because the mean of its divisors is an integer number (10700545).

Almost surely, 2^21401089 is an apocalyptic number.

It is an amenable number.

21401089 is a deficient number, since it is larger than the sum of its proper divisors (1).

21401089 is an equidigital number, since it uses as much as digits as its factorization.

21401089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21401089 is about 4626.1311049299. The cubic root of 21401089 is about 277.6378191587.

The spelling of 21401089 in words is "twenty-one million, four hundred one thousand, eighty-nine".