21448369 has 6 divisors (see below), whose sum is σ = 21595110. Its totient is φ = 21302496.

The previous prime is 21448337. The next prime is 21448379. The reversal of 21448369 is 96384412.

It can be written as a sum of positive squares in 3 ways, for example, as 17977600 + 3470769 = 4240^2 + 1863^2 .

It is not a de Polignac number, because 21448369 - 2⁵ = 21448337 is a prime.

It is a super-2 number, since 2×21448369² = 920065065520322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21448379) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 52237 + ... + 52645.

It is an arithmetic number, because the mean of its divisors is an integer number (3599185).

Almost surely, 2^21448369 is an apocalyptic number.

It is an amenable number.

21448369 is a deficient number, since it is larger than the sum of its proper divisors (146741).

21448369 is an frugal number, since it uses more digits than its factorization.

21448369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 867 (or 638 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 21448369 is about 4631.2383872999. The cubic root of 21448369 is about 277.8421243583.

The spelling of 21448369 in words is "twenty-one million, four hundred forty-eight thousand, three hundred sixty-nine".