21867938 has 4 divisors (see below), whose sum is σ = 32801910. Its totient is φ = 10933968.

The previous prime is 21867931. The next prime is 21867941. The reversal of 21867938 is 83976812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13300609 + 8567329 = 3647^2 + 2927^2 .

It is not an unprimeable number, because it can be changed into a prime (21867931) by changing a digit.

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 as a sum of consecutive naturals, namely, 5466983 + ... + 5466986.

Almost surely, 2^21867938 is an apocalyptic number.

21867938 is a deficient number, since it is larger than the sum of its proper divisors (10933972).

21867938 is a wasteful number, since it uses less digits than its factorization.

21867938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10933971.

The product of its digits is 145152, while the sum is 44.

The square root of 21867938 is about 4676.3167129697. The cubic root of 21867938 is about 279.6421363523.

The spelling of 21867938 in words is "twenty-one million, eight hundred sixty-seven thousand, nine hundred thirty-eight".