21486538 has 16 divisors (see below), whose sum is σ = 34469064. Its totient is φ = 10009600.

The previous prime is 21486527. The next prime is 21486539. The reversal of 21486538 is 83568412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18378369 + 3108169 = 4287^2 + 1763^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21486497 and 21486506.

It is not an unprimeable number, because it can be changed into a prime (21486539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 306 + ... + 6562.

Almost surely, 2^21486538 is an apocalyptic number.

21486538 is a deficient number, since it is larger than the sum of its proper divisors (12982526).

21486538 is a wasteful number, since it uses less digits than its factorization.

21486538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6377.

The product of its digits is 46080, while the sum is 37.

The square root of 21486538 is about 4635.3573756508. The cubic root of 21486538 is about 278.0068404024.

The spelling of 21486538 in words is "twenty-one million, four hundred eighty-six thousand, five hundred thirty-eight".