20133521 has 8 divisors (see below), whose sum is σ = 21357600. Its totient is φ = 18925920.

The previous prime is 20133517. The next prime is 20133527. The reversal of 20133521 is 12533102.

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 20133521 - 2² = 20133517 is a prime.

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 20133521.

It is not an unprimeable number, because it can be changed into a prime (20133527) 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, 1556 + ... + 6533.

It is an arithmetic number, because the mean of its divisors is an integer number (2669700).

Almost surely, 2^20133521 is an apocalyptic number.

It is an amenable number.

20133521 is a deficient number, since it is larger than the sum of its proper divisors (1224079).

20133521 is a wasteful number, since it uses less digits than its factorization.

20133521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8239.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 20133521 is about 4487.0392242547. The cubic root of 20133521 is about 272.0444753182.

Adding to 20133521 its reverse (12533102), we get a palindrome (32666623).

The spelling of 20133521 in words is "twenty million, one hundred thirty-three thousand, five hundred twenty-one".