33660021 has 4 divisors (see below), whose sum is σ = 44880032. Its totient is φ = 22440012.

The previous prime is 33659999. The next prime is 33660071. The reversal of 33660021 is 12006633.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 33660021 - 2¹¹ = 33657973 is a prime.

It is a super-2 number, since 2×33660021² = 2265994027440882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 33660021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (33660071) 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 3 ways as a sum of consecutive naturals, for example, 5610001 + ... + 5610006.

It is an arithmetic number, because the mean of its divisors is an integer number (11220008).

Almost surely, 2^33660021 is an apocalyptic number.

It is an amenable number.

33660021 is a deficient number, since it is larger than the sum of its proper divisors (11220011).

33660021 is a wasteful number, since it uses less digits than its factorization.

33660021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11220010.

The product of its (nonzero) digits is 648, while the sum is 21.

The square root of 33660021 is about 5801.7256915507. The cubic root of 33660021 is about 322.8777569730.

Adding to 33660021 its reverse (12006633), we get a palindrome (45666654).

The spelling of 33660021 in words is "thirty-three million, six hundred sixty thousand, twenty-one".