21330553 has 8 divisors (see below), whose sum is σ = 21728000. Its totient is φ = 20936448.

The previous prime is 21330503. The next prime is 21330581. The reversal of 21330553 is 35503312.

It is a happy number.

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 21330553 - 2¹³ = 21322361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21330503) 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, 14548 + ... + 15946.

It is an arithmetic number, because the mean of its divisors is an integer number (2716000).

Almost surely, 2^21330553 is an apocalyptic number.

It is an amenable number.

21330553 is a deficient number, since it is larger than the sum of its proper divisors (397447).

21330553 is a wasteful number, since it uses less digits than its factorization.

21330553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1671.

The product of its (nonzero) digits is 1350, while the sum is 22.

The square root of 21330553 is about 4618.5011637976. The cubic root of 21330553 is about 277.3324606201.

Adding to 21330553 its reverse (35503312), we get a palindrome (56833865).

The spelling of 21330553 in words is "twenty-one million, three hundred thirty thousand, five hundred fifty-three".