21330557 has 8 divisors (see below), whose sum is σ = 21632832. Its totient is φ = 21030400.

The previous prime is 21330503. The next prime is 21330581. The reversal of 21330557 is 75503312.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21330557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21330157) 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, 32957 + ... + 33597.

It is an arithmetic number, because the mean of its divisors is an integer number (2704104).

Almost surely, 2^21330557 is an apocalyptic number.

It is an amenable number.

21330557 is a deficient number, since it is larger than the sum of its proper divisors (302275).

21330557 is a wasteful number, since it uses less digits than its factorization.

21330557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059.

The product of its (nonzero) digits is 3150, while the sum is 26.

The square root of 21330557 is about 4618.5015968385. The cubic root of 21330557 is about 277.3324779557.

Adding to 21330557 its reverse (75503312), we get a palindrome (96833869).

The spelling of 21330557 in words is "twenty-one million, three hundred thirty thousand, five hundred fifty-seven".