21462240 has 96 divisors (see below), whose sum is σ = 68808096. Its totient is φ = 5621760.

The previous prime is 21462239. The next prime is 21462251. The reversal of 21462240 is 4226412.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28914 + ... + 29646.

It is an arithmetic number, because the mean of its divisors is an integer number (716751).

Almost surely, 2^21462240 is an apocalyptic number.

21462240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21462240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34404048).

21462240 is an abundant number, since it is smaller than the sum of its proper divisors (47345856).

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

21462240 is a wasteful number, since it uses less digits than its factorization.

21462240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 812 (or 804 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 21462240 is about 4632.7356928709. The cubic root of 21462240 is about 277.9020064190.

Adding to 21462240 its reverse (4226412), we get a palindrome (25688652).

The spelling of 21462240 in words is "twenty-one million, four hundred sixty-two thousand, two hundred forty".