21082440 has 32 divisors (see below), whose sum is σ = 63247680. Its totient is φ = 5621952.

The previous prime is 21082423. The next prime is 21082447. The reversal of 21082440 is 4428012.

It is not an unprimeable number, because it can be changed into a prime (21082447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87724 + ... + 87963.

It is an arithmetic number, because the mean of its divisors is an integer number (1976490).

Almost surely, 2^21082440 is an apocalyptic number.

21082440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21082440 is an abundant number, since it is smaller than the sum of its proper divisors (42165240).

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

21082440 is a wasteful number, since it uses less digits than its factorization.

21082440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175701 (or 175697 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 21082440 is about 4591.5618257843. The cubic root of 21082440 is about 276.2529711739.

The spelling of 21082440 in words is "twenty-one million, eighty-two thousand, four hundred forty".