21113240 has 32 divisors (see below), whose sum is σ = 47958480. Its totient is φ = 8364672.

The previous prime is 21113231. The next prime is 21113243. The reversal of 21113240 is 4231112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21113243) 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, 1814 + ... + 6746.

Almost surely, 2^21113240 is an apocalyptic number.

21113240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21113240 is an abundant number, since it is smaller than the sum of its proper divisors (26845240).

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

21113240 is a wasteful number, since it uses less digits than its factorization.

21113240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5051 (or 5047 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21113240 is about 4594.9145802724. The cubic root of 21113240 is about 276.3874346007.

Adding to 21113240 its reverse (4231112), we get a palindrome (25344352).

The spelling of 21113240 in words is "twenty-one million, one hundred thirteen thousand, two hundred forty".