21112240 has 40 divisors (see below), whose sum is σ = 50675328. Its totient is φ = 8171520.

The previous prime is 21112207. The next prime is 21112241. The reversal of 21112240 is 4221112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 21112240.

It is not an unprimeable number, because it can be changed into a prime (21112241) 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, 1777 + ... + 6736.

Almost surely, 2^21112240 is an apocalyptic number.

21112240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21112240 is an abundant number, since it is smaller than the sum of its proper divisors (29563088).

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

21112240 is a wasteful number, since it uses less digits than its factorization.

21112240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8557 (or 8551 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21112240 is about 4594.8057630329. The cubic root of 21112240 is about 276.3830709597.

Adding to 21112240 its reverse (4221112), we get a palindrome (25333352).

The spelling of 21112240 in words is "twenty-one million, one hundred twelve thousand, two hundred forty".