21330001 has 12 divisors (see below), whose sum is σ = 26795776. Its totient is φ = 16620120.

The previous prime is 21329999. The next prime is 21330047. The reversal of 21330001 is 10003312.

21330001 = 293² + 294² + ... + 446².

It is not a de Polignac number, because 21330001 - 2¹ = 21329999 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21330001.

It is not an unprimeable number, because it can be changed into a prime (21331001) 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 11 ways as a sum of consecutive naturals, for example, 11745 + ... + 13438.

Almost surely, 2^21330001 is an apocalyptic number.

It is an amenable number.

21330001 is a deficient number, since it is larger than the sum of its proper divisors (5465775).

21330001 is a wasteful number, since it uses less digits than its factorization.

21330001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25212 (or 25201 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21330001 is about 4618.4414037638. The cubic root of 21330001 is about 277.3300682953.

Adding to 21330001 its reverse (10003312), we get a palindrome (31333313).

The spelling of 21330001 in words is "twenty-one million, three hundred thirty thousand, one".