21986441 has 4 divisors (see below), whose sum is σ = 22037652. Its totient is φ = 21935232.

The previous prime is 21986431. The next prime is 21986449. The reversal of 21986441 is 14468912.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10426441 + 11560000 = 3229^2 + 3400^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21986441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21986449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24956 + ... + 25821.

It is an arithmetic number, because the mean of its divisors is an integer number (5509413).

Almost surely, 2^21986441 is an apocalyptic number.

It is an amenable number.

21986441 is a deficient number, since it is larger than the sum of its proper divisors (51211).

21986441 is an equidigital number, since it uses as much as digits as its factorization.

21986441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51210.

The product of its digits is 13824, while the sum is 35.

The square root of 21986441 is about 4688.9701427926. The cubic root of 21986441 is about 280.1463563092.

The spelling of 21986441 in words is "twenty-one million, nine hundred eighty-six thousand, four hundred forty-one".