21076440 has 128 divisors (see below), whose sum is σ = 78865920. Its totient is φ = 4377600.

The previous prime is 21076427. The next prime is 21076463. The reversal of 21076440 is 4467012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21076440.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 8100 + ... + 10380.

It is an arithmetic number, because the mean of its divisors is an integer number (616140).

Almost surely, 2^21076440 is an apocalyptic number.

21076440 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 21076440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39432960).

21076440 is an abundant number, since it is smaller than the sum of its proper divisors (57789480).

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

21076440 is a wasteful number, since it uses less digits than its factorization.

21076440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2313 (or 2309 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21076440 is about 4590.9084068406. The cubic root of 21076440 is about 276.2267617615.

The spelling of 21076440 in words is "twenty-one million, seventy-six thousand, four hundred forty".