21438988 has 6 divisors (see below), whose sum is σ = 37518236. Its totient is φ = 10719492.

The previous prime is 21438961. The next prime is 21439079. The reversal of 21438988 is 88983412.

It is a plaindrome in base 11.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2679870 + ... + 2679877.

Almost surely, 2^21438988 is an apocalyptic number.

It is an amenable number.

21438988 is a deficient number, since it is larger than the sum of its proper divisors (16079248).

21438988 is a wasteful number, since it uses less digits than its factorization.

21438988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5359751 (or 5359749 counting only the distinct ones).

The product of its digits is 110592, while the sum is 43.

The square root of 21438988 is about 4630.2254804707. The cubic root of 21438988 is about 277.8016113002.

The spelling of 21438988 in words is "twenty-one million, four hundred thirty-eight thousand, nine hundred eighty-eight".