20330021 has 4 divisors (see below), whose sum is σ = 20485344. Its totient is φ = 20174700.

The previous prime is 20329993. The next prime is 20330047. The reversal of 20330021 is 12003302.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20330021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20329984 and 20330011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20330071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77465 + ... + 77726.

It is an arithmetic number, because the mean of its divisors is an integer number (5121336).

Almost surely, 2^20330021 is an apocalyptic number.

It is an amenable number.

20330021 is a deficient number, since it is larger than the sum of its proper divisors (155323).

20330021 is a wasteful number, since it uses less digits than its factorization.

20330021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155322.

The product of its (nonzero) digits is 36, while the sum is 11.

The square root of 20330021 is about 4508.8824557755. The cubic root of 20330021 is about 272.9266486595.

Adding to 20330021 its reverse (12003302), we get a palindrome (32333323).

The spelling of 20330021 in words is "twenty million, three hundred thirty thousand, twenty-one".