21438386 has 4 divisors (see below), whose sum is σ = 32157582. Its totient is φ = 10719192.

The previous prime is 21438359. The next prime is 21438401. The reversal of 21438386 is 68383412.

It is a happy number.

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., 14250625 + 7187761 = 3775^2 + 2681^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5359595 + ... + 5359598.

Almost surely, 2^21438386 is an apocalyptic number.

21438386 is a deficient number, since it is larger than the sum of its proper divisors (10719196).

21438386 is a wasteful number, since it uses less digits than its factorization.

21438386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10719195.

The product of its digits is 27648, while the sum is 35.

The square root of 21438386 is about 4630.1604723811. The cubic root of 21438386 is about 277.7990110821.

The spelling of 21438386 in words is "twenty-one million, four hundred thirty-eight thousand, three hundred eighty-six".