21033689 has 4 divisors (see below), whose sum is σ = 21045156. Its totient is φ = 21022224.

The previous prime is 21033667. The next prime is 21033721. The reversal of 21033689 is 98633012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 2689600 + 18344089 = 1640^2 + 4283^2 .

It is not a de Polignac number, because 21033689 - 2⁸ = 21033433 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21033659) 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, 2294 + ... + 6879.

It is an arithmetic number, because the mean of its divisors is an integer number (5261289).

Almost surely, 2^21033689 is an apocalyptic number.

It is an amenable number.

21033689 is a deficient number, since it is larger than the sum of its proper divisors (11467).

21033689 is an equidigital number, since it uses as much as digits as its factorization.

21033689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11466.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 21033689 is about 4586.2499931862. The cubic root of 21033689 is about 276.0398711915.

The spelling of 21033689 in words is "twenty-one million, thirty-three thousand, six hundred eighty-nine".