21353345 has 8 divisors (see below), whose sum is σ = 27595176. Its totient is φ = 15768576.

The previous prime is 21353281. The next prime is 21353347. The reversal of 21353345 is 54335312.

It can be written as a sum of positive squares in 4 ways, for example, as 303601 + 21049744 = 551^2 + 4588^2 .

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 21353345 - 2⁶ = 21353281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21353347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164192 + ... + 164321.

It is an arithmetic number, because the mean of its divisors is an integer number (3449397).

Almost surely, 2^21353345 is an apocalyptic number.

It is an amenable number.

21353345 is a deficient number, since it is larger than the sum of its proper divisors (6241831).

21353345 is a wasteful number, since it uses less digits than its factorization.

21353345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328531.

The product of its digits is 5400, while the sum is 26.

The square root of 21353345 is about 4620.9679721894. The cubic root of 21353345 is about 277.4312033552.

Adding to 21353345 its reverse (54335312), we get a palindrome (75688657).

The spelling of 21353345 in words is "twenty-one million, three hundred fifty-three thousand, three hundred forty-five".