21533345 has 8 divisors (see below), whose sum is σ = 25865664. Its totient is φ = 17209584.

The previous prime is 21533333. The next prime is 21533357. The reversal of 21533345 is 54333512.

It is an interprime number because it is at equal distance from previous prime (21533333) and next prime (21533357).

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 21533345 - 2¹⁴ = 21516961 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6812 + ... + 9458.

It is an arithmetic number, because the mean of its divisors is an integer number (3233208).

Almost surely, 2^21533345 is an apocalyptic number.

It is an amenable number.

21533345 is a deficient number, since it is larger than the sum of its proper divisors (4332319).

21533345 is a wasteful number, since it uses less digits than its factorization.

21533345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4279.

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

The square root of 21533345 is about 4640.4035384867. The cubic root of 21533345 is about 278.2085671537.

Adding to 21533345 its reverse (54333512), we get a palindrome (75866857).

The spelling of 21533345 in words is "twenty-one million, five hundred thirty-three thousand, three hundred forty-five".