21033730 has 32 divisors (see below), whose sum is σ = 39916800. Its totient is φ = 7964352.

The previous prime is 21033721. The next prime is 21033737. The reversal of 21033730 is 3733012.

It is a junction number, because it is equal to n+sod(n) for n = 21033698 and 21033707.

It is not an unprimeable number, because it can be changed into a prime (21033737) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24651 + ... + 25489.

It is an arithmetic number, because the mean of its divisors is an integer number (1247400).

Almost surely, 2^21033730 is an apocalyptic number.

21033730 is a deficient number, since it is larger than the sum of its proper divisors (18883070).

21033730 is a wasteful number, since it uses less digits than its factorization.

21033730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 978.

The product of its (nonzero) digits is 378, while the sum is 19.

The square root of 21033730 is about 4586.2544630668. The cubic root of 21033730 is about 276.0400505487.

Adding to 21033730 its reverse (3733012), we get a palindrome (24766742).

The spelling of 21033730 in words is "twenty-one million, thirty-three thousand, seven hundred thirty".