21378338 has 8 divisors (see below), whose sum is σ = 32260032. Its totient is φ = 10624996.

The previous prime is 21378319. The next prime is 21378347. The reversal of 21378338 is 83387312.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21378298 and 21378307.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31670 + ... + 32337.

It is an arithmetic number, because the mean of its divisors is an integer number (4032504).

Almost surely, 2^21378338 is an apocalyptic number.

21378338 is a deficient number, since it is larger than the sum of its proper divisors (10881694).

21378338 is a wasteful number, since it uses less digits than its factorization.

21378338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64176.

The product of its digits is 24192, while the sum is 35.

The square root of 21378338 is about 4623.6714848700. The cubic root of 21378338 is about 277.5394008389.

The spelling of 21378338 in words is "twenty-one million, three hundred seventy-eight thousand, three hundred thirty-eight".