21033516 has 48 divisors (see below), whose sum is σ = 56376320. Its totient is φ = 5978880.

The previous prime is 21033479. The next prime is 21033517. The reversal of 21033516 is 61533012.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 21033492 and 21033501.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 19725 + ... + 20763.

Almost surely, 2^21033516 is an apocalyptic number.

It is an amenable number.

21033516 is an abundant number, since it is smaller than the sum of its proper divisors (35342804).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21033516 is a wasteful number, since it uses less digits than its factorization.

21033516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1294 (or 1292 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 21033516 is about 4586.2311324224. The cubic root of 21033516 is about 276.0391143893.

Adding to 21033516 its reverse (61533012), we get a palindrome (82566528).

The spelling of 21033516 in words is "twenty-one million, thirty-three thousand, five hundred sixteen".