21872378 has 8 divisors (see below), whose sum is σ = 35791200. Its totient is φ = 9941980.

The previous prime is 21872377. The next prime is 21872399. The reversal of 21872378 is 87327812.

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

It is not an unprimeable number, because it can be changed into a prime (21872371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 497078 + ... + 497121.

It is an arithmetic number, because the mean of its divisors is an integer number (4473900).

Almost surely, 2^21872378 is an apocalyptic number.

21872378 is a deficient number, since it is larger than the sum of its proper divisors (13918822).

21872378 is a wasteful number, since it uses less digits than its factorization.

21872378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 994212.

The product of its digits is 37632, while the sum is 38.

The square root of 21872378 is about 4676.7914214769. The cubic root of 21872378 is about 279.6610609695.

The spelling of 21872378 in words is "twenty-one million, eight hundred seventy-two thousand, three hundred seventy-eight".