21168538 has 8 divisors (see below), whose sum is σ = 31781088. Its totient is φ = 10574844.

The previous prime is 21168529. The next prime is 21168541. The reversal of 21168538 is 83586112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1456 + ... + 6667.

It is an arithmetic number, because the mean of its divisors is an integer number (3972636).

Almost surely, 2^21168538 is an apocalyptic number.

21168538 is a deficient number, since it is larger than the sum of its proper divisors (10612550).

21168538 is a wasteful number, since it uses less digits than its factorization.

21168538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9428.

The product of its digits is 11520, while the sum is 34.

The square root of 21168538 is about 4600.9279498814. The cubic root of 21168538 is about 276.6285210550.

The spelling of 21168538 in words is "twenty-one million, one hundred sixty-eight thousand, five hundred thirty-eight".