21033512 has 16 divisors (see below), whose sum is σ = 39801300. Its totient is φ = 10419840.

The previous prime is 21033479. The next prime is 21033517. The reversal of 21033512 is 21533012.

It can be written as a sum of positive squares in 2 ways, for example, as 21031396 + 2116 = 4586^2 + 46^2 .

It is not an unprimeable number, because it can be changed into a prime (21033517) 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, 11189 + ... + 12932.

Almost surely, 2^21033512 is an apocalyptic number.

It is an amenable number.

21033512 is a deficient number, since it is larger than the sum of its proper divisors (18767788).

21033512 is a wasteful number, since it uses less digits than its factorization.

21033512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24236 (or 24232 counting only the distinct ones).

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

The square root of 21033512 is about 4586.2306963344. The cubic root of 21033512 is about 276.0390968909.

Adding to 21033512 its reverse (21533012), we get a palindrome (42566524).

Subtracting 21033512 from its reverse (21533012), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 21033512 in words is "twenty-one million, thirty-three thousand, five hundred twelve".