21133653 has 8 divisors (see below), whose sum is σ = 28200288. Its totient is φ = 14078064.

The previous prime is 21133649. The next prime is 21133667. The reversal of 21133653 is 35633112.

It is a happy number.

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

It is not a de Polignac number, because 21133653 - 2² = 21133649 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133603) 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, 4251 + ... + 7767.

It is an arithmetic number, because the mean of its divisors is an integer number (3525036).

Almost surely, 2^21133653 is an apocalyptic number.

It is an amenable number.

21133653 is a deficient number, since it is larger than the sum of its proper divisors (7066635).

21133653 is a wasteful number, since it uses less digits than its factorization.

21133653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5523.

The product of its digits is 1620, while the sum is 24.

The square root of 21133653 is about 4597.1353036429. The cubic root of 21133653 is about 276.4764795068.

Adding to 21133653 its reverse (35633112), we get a palindrome (56766765).

The spelling of 21133653 in words is "twenty-one million, one hundred thirty-three thousand, six hundred fifty-three".