21733240 has 32 divisors (see below), whose sum is σ = 49734000. Its totient is φ = 8545024.

The previous prime is 21733219. The next prime is 21733241. The reversal of 21733240 is 4233712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21733241) 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, 2245 + ... + 6964.

Almost surely, 2^21733240 is an apocalyptic number.

21733240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21733240 is an abundant number, since it is smaller than the sum of its proper divisors (28000760).

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

21733240 is a wasteful number, since it uses less digits than its factorization.

21733240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9279 (or 9275 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 21733240 is about 4661.8923196487. The cubic root of 21733240 is about 279.0667911332.

Adding to 21733240 its reverse (4233712), we get a palindrome (25966952).

The spelling of 21733240 in words is "twenty-one million, seven hundred thirty-three thousand, two hundred forty".