21138116 has 12 divisors (see below), whose sum is σ = 37148160. Its totient is φ = 10524360.

The previous prime is 21138113. The next prime is 21138121. The reversal of 21138116 is 61183112.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21138091 and 21138100.

It is not an unprimeable number, because it can be changed into a prime (21138113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10100 + ... + 12011.

It is an arithmetic number, because the mean of its divisors is an integer number (3095680).

Almost surely, 2^21138116 is an apocalyptic number.

It is an amenable number.

21138116 is a deficient number, since it is larger than the sum of its proper divisors (16010044).

21138116 is a wasteful number, since it uses less digits than its factorization.

21138116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22354 (or 22352 counting only the distinct ones).

The product of its digits is 288, while the sum is 23.

The square root of 21138116 is about 4597.6206890086. The cubic root of 21138116 is about 276.4959402168.

It can be divided in two parts, 21 and 138116, that multiplied together give a triangular number (2900436 = T₂₄₀₈).

The spelling of 21138116 in words is "twenty-one million, one hundred thirty-eight thousand, one hundred sixteen".