21353449 has 8 divisors (see below), whose sum is σ = 23312072. Its totient is φ = 19440000.

The previous prime is 21353443. The next prime is 21353459. The reversal of 21353449 is 94435312.

It can be written as a sum of positive squares in 4 ways, for example, as 7155625 + 14197824 = 2675^2 + 3768^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21353449 - 2³ = 21353441 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21353449.

It is not an unprimeable number, because it can be changed into a prime (21353441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10302 + ... + 12199.

It is an arithmetic number, because the mean of its divisors is an integer number (2914009).

Almost surely, 2^21353449 is an apocalyptic number.

It is an amenable number.

21353449 is a deficient number, since it is larger than the sum of its proper divisors (1958623).

21353449 is a wasteful number, since it uses less digits than its factorization.

21353449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22587.

The product of its digits is 12960, while the sum is 31.

The square root of 21353449 is about 4620.9792252292. The cubic root of 21353449 is about 277.4316537577.

The spelling of 21353449 in words is "twenty-one million, three hundred fifty-three thousand, four hundred forty-nine".