21082240 has 32 divisors (see below), whose sum is σ = 50401260. Its totient is φ = 8432640.

The previous prime is 21082213. The next prime is 21082253. The reversal of 21082240 is 4228012.

It can be written as a sum of positive squares in 2 ways, for example, as 20575296 + 506944 = 4536^2 + 712^2 .

It is a tau number, because it is divible by the number of its divisors (32).

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, 15831 + ... + 17110.

Almost surely, 2^21082240 is an apocalyptic number.

21082240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21082240 is an abundant number, since it is smaller than the sum of its proper divisors (29319020).

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

21082240 is an equidigital number, since it uses as much as digits as its factorization.

21082240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32960 (or 32948 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 21082240 is about 4591.5400466510. The cubic root of 21082240 is about 276.2520976070.

The spelling of 21082240 in words is "twenty-one million, eighty-two thousand, two hundred forty".