21388382 has 8 divisors (see below), whose sum is σ = 32103000. Its totient is φ = 10687384.

The previous prime is 21388373. The next prime is 21388417. The reversal of 21388382 is 28388312.

It is a happy number.

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

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, 2744 + ... + 7092.

It is an arithmetic number, because the mean of its divisors is an integer number (4012875).

Almost surely, 2^21388382 is an apocalyptic number.

21388382 is a deficient number, since it is larger than the sum of its proper divisors (10714618).

21388382 is a wasteful number, since it uses less digits than its factorization.

21388382 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6810.

The product of its digits is 18432, while the sum is 35.

The square root of 21388382 is about 4624.7575071565. The cubic root of 21388382 is about 277.5828586807.

The spelling of 21388382 in words is "twenty-one million, three hundred eighty-eight thousand, three hundred eighty-two".