21533338 has 4 divisors (see below), whose sum is σ = 32300010. Its totient is φ = 10766668.

The previous prime is 21533333. The next prime is 21533357. The reversal of 21533338 is 83333512.

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., 13082689 + 8450649 = 3617^2 + 2907^2 .

It is not an unprimeable number, because it can be changed into a prime (21533333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5383333 + ... + 5383336.

Almost surely, 2^21533338 is an apocalyptic number.

21533338 is a deficient number, since it is larger than the sum of its proper divisors (10766672).

21533338 is a wasteful number, since it uses less digits than its factorization.

21533338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10766671.

The product of its digits is 6480, while the sum is 28.

The square root of 21533338 is about 4640.4027842419. The cubic root of 21533338 is about 278.2085370072.

The spelling of 21533338 in words is "twenty-one million, five hundred thirty-three thousand, three hundred thirty-eight".