21115040 has 24 divisors (see below), whose sum is σ = 49884660. Its totient is φ = 8445952.

The previous prime is 21115027. The next prime is 21115063. The reversal of 21115040 is 4051112.

It can be written as a sum of positive squares in 2 ways, for example, as 19254544 + 1860496 = 4388^2 + 1364^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65825 + ... + 66144.

Almost surely, 2^21115040 is an apocalyptic number.

21115040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21115040 is an abundant number, since it is smaller than the sum of its proper divisors (28769620).

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

21115040 is a wasteful number, since it uses less digits than its factorization.

21115040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131984 (or 131976 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 21115040 is about 4595.1104448098. The cubic root of 21115040 is about 276.3952888073.

Adding to 21115040 its reverse (4051112), we get a palindrome (25166152).

It can be divided in two parts, 211 and 15040, that added together give a palindrome (15251).

The spelling of 21115040 in words is "twenty-one million, one hundred fifteen thousand, forty".