21919378 has 16 divisors (see below), whose sum is σ = 35743680. Its totient is φ = 10020816.

The previous prime is 21919363. The next prime is 21919393. The reversal of 21919378 is 87391912.

It is an interprime number because it is at equal distance from previous prime (21919363) and next prime (21919393).

It is a self number, because there is not a number n which added to its sum of digits gives 21919378.

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 7 ways as a sum of consecutive naturals, for example, 1158 + ... + 6721.

It is an arithmetic number, because the mean of its divisors is an integer number (2233980).

Almost surely, 2^21919378 is an apocalyptic number.

21919378 is a deficient number, since it is larger than the sum of its proper divisors (13824302).

21919378 is a wasteful number, since it uses less digits than its factorization.

21919378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8001.

The product of its digits is 27216, while the sum is 40.

The square root of 21919378 is about 4681.8135375087. The cubic root of 21919378 is about 279.8612322586.

The spelling of 21919378 in words is "twenty-one million, nine hundred nineteen thousand, three hundred seventy-eight".