21033144 has 48 divisors (see below), whose sum is σ = 62145720. Its totient is φ = 6373440.

The previous prime is 21033127. The next prime is 21033151. The reversal of 21033144 is 44133012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12487 + ... + 14070.

Almost surely, 2^21033144 is an apocalyptic number.

21033144 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21033144 is an abundant number, since it is smaller than the sum of its proper divisors (41112576).

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

21033144 is a wasteful number, since it uses less digits than its factorization.

21033144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26580 (or 26573 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21033144 is about 4586.1905760664. The cubic root of 21033144 is about 276.0374870317.

Adding to 21033144 its reverse (44133012), we get a palindrome (65166156).

The spelling of 21033144 in words is "twenty-one million, thirty-three thousand, one hundred forty-four".