21683138 has 4 divisors (see below), whose sum is σ = 32524710. Its totient is φ = 10841568.

The previous prime is 21683131. The next prime is 21683141. The reversal of 21683138 is 83138612.

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., 11992369 + 9690769 = 3463^2 + 3113^2 .

It is not an unprimeable number, because it can be changed into a prime (21683131) 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, 5420783 + ... + 5420786.

Almost surely, 2^21683138 is an apocalyptic number.

21683138 is a deficient number, since it is larger than the sum of its proper divisors (10841572).

21683138 is a wasteful number, since it uses less digits than its factorization.

21683138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10841571.

The product of its digits is 6912, while the sum is 32.

The square root of 21683138 is about 4656.5156501401. The cubic root of 21683138 is about 278.8521803601.

The spelling of 21683138 in words is "twenty-one million, six hundred eighty-three thousand, one hundred thirty-eight".