21938364 has 120 divisors (see below), whose sum is σ = 69521760. Its totient is φ = 5889024.

The previous prime is 21938353. The next prime is 21938377. The reversal of 21938364 is 46383912.

21938364 is a `hidden beast` number, since 219 + 383 + 64 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 38272 + ... + 38840.

It is an arithmetic number, because the mean of its divisors is an integer number (579348).

Almost surely, 2^21938364 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21938364, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34760880).

21938364 is an abundant number, since it is smaller than the sum of its proper divisors (47583396).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21938364 is a wasteful number, since it uses less digits than its factorization.

21938364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609 (or 598 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21938364 is about 4683.8407317073. The cubic root of 21938364 is about 279.9420118010.

It can be divided in two parts, 219 and 38364, that added together give a palindrome (38583).

The spelling of 21938364 in words is "twenty-one million, nine hundred thirty-eight thousand, three hundred sixty-four".