21378844 has 6 divisors (see below), whose sum is σ = 37412984. Its totient is φ = 10689420.

The previous prime is 21378817. The next prime is 21378883. The reversal of 21378844 is 44887312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2672352 + ... + 2672359.

Almost surely, 2^21378844 is an apocalyptic number.

It is an amenable number.

21378844 is a deficient number, since it is larger than the sum of its proper divisors (16034140).

21378844 is a wasteful number, since it uses less digits than its factorization.

21378844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5344715 (or 5344713 counting only the distinct ones).

The product of its digits is 43008, while the sum is 37.

The square root of 21378844 is about 4623.7262029666. The cubic root of 21378844 is about 277.5415904982.

It can be divided in two parts, 21378 and 844, that added together give a palindrome (22222).

The spelling of 21378844 in words is "twenty-one million, three hundred seventy-eight thousand, eight hundred forty-four".