21986449 has 2 divisors, whose sum is σ = 21986450. Its totient is φ = 21986448.

The previous prime is 21986431. The next prime is 21986507. The reversal of 21986449 is 94468912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19079424 + 2907025 = 4368^2 + 1705^2 .

It is a cyclic number.

It is not a de Polignac number, because 21986449 - 2⁵ = 21986417 is a prime.

It is not a weakly prime, because it can be changed into another prime (21986849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10993224 + 10993225.

It is an arithmetic number, because the mean of its divisors is an integer number (10993225).

Almost surely, 2^21986449 is an apocalyptic number.

It is an amenable number.

21986449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21986449 is an equidigital number, since it uses as much as digits as its factorization.

21986449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 43.

The square root of 21986449 is about 4688.9709958583. The cubic root of 21986449 is about 280.1463902873.

It can be divided in two parts, 219 and 86449, that added together give a palindrome (86668).

The spelling of 21986449 in words is "twenty-one million, nine hundred eighty-six thousand, four hundred forty-nine".