21733212 has 24 divisors (see below), whose sum is σ = 50787856. Its totient is φ = 7233408.

The previous prime is 21733193. The next prime is 21733219. The reversal of 21733212 is 21233712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21733219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12288 + ... + 13944.

Almost surely, 2^21733212 is an apocalyptic number.

It is an amenable number.

21733212 is an abundant number, since it is smaller than the sum of its proper divisors (29054644).

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

21733212 is a wasteful number, since it uses less digits than its factorization.

21733212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2757 (or 2755 counting only the distinct ones).

The product of its digits is 504, while the sum is 21.

The square root of 21733212 is about 4661.8893165754. The cubic root of 21733212 is about 279.0666712880.

Adding to 21733212 its reverse (21233712), we get a palindrome (42966924).

Subtracting from 21733212 its reverse (21233712), we obtain a triangular number (499500 = T₉₉₉).

It can be divided in two parts, 21733 and 212, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21733212 in words is "twenty-one million, seven hundred thirty-three thousand, two hundred twelve".