21262240 has 48 divisors (see below), whose sum is σ = 53193672. Its totient is φ = 8003584.

The previous prime is 21262237. The next prime is 21262247. The reversal of 21262240 is 4226212.

It can be written as a sum of positive squares in 4 ways, for example, as 12759184 + 8503056 = 3572^2 + 2916^2 .

It is not an unprimeable number, because it can be changed into a prime (21262247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1189 + ... + 6628.

Almost surely, 2^21262240 is an apocalyptic number.

21262240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21262240 is an abundant number, since it is smaller than the sum of its proper divisors (31931432).

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

21262240 is a wasteful number, since it uses less digits than its factorization.

21262240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7849 (or 7841 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 21262240 is about 4611.0996519269. The cubic root of 21262240 is about 277.0360833496.

Adding to 21262240 its reverse (4226212), we get a palindrome (25488452).

The spelling of 21262240 in words is "twenty-one million, two hundred sixty-two thousand, two hundred forty".