21278382 has 8 divisors (see below), whose sum is σ = 42556776. Its totient is φ = 7092792.

The previous prime is 21278363. The next prime is 21278393. The reversal of 21278382 is 28387212.

It is a sphenic number, since it is the product of 3 distinct primes.

21278382 is an admirable number.

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 3 ways as a sum of consecutive naturals, for example, 1773193 + ... + 1773204.

It is an arithmetic number, because the mean of its divisors is an integer number (5319597).

Almost surely, 2^21278382 is an apocalyptic number.

21278382 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21278382 is a wasteful number, since it uses less digits than its factorization.

21278382 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3546402.

The product of its digits is 10752, while the sum is 33.

The square root of 21278382 is about 4612.8496615433. The cubic root of 21278382 is about 277.1061729428.

The spelling of 21278382 in words is "twenty-one million, two hundred seventy-eight thousand, three hundred eighty-two".