21412240 has 40 divisors (see below), whose sum is σ = 52407360. Its totient is φ = 8113536.

The previous prime is 21412219. The next prime is 21412267. The reversal of 21412240 is 4221412.

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

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

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, 5524 + ... + 8563.

It is an arithmetic number, because the mean of its divisors is an integer number (1310184).

Almost surely, 2^21412240 is an apocalyptic number.

21412240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21412240 is an abundant number, since it is smaller than the sum of its proper divisors (30995120).

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

21412240 is a wasteful number, since it uses less digits than its factorization.

21412240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14119 (or 14113 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21412240 is about 4627.3361667378. The cubic root of 21412240 is about 277.6860316861.

Adding to 21412240 its reverse (4221412), we get a palindrome (25633652).

The spelling of 21412240 in words is "twenty-one million, four hundred twelve thousand, two hundred forty".