21108874 has 4 divisors (see below), whose sum is σ = 31663314. Its totient is φ = 10554436.

The previous prime is 21108869. The next prime is 21108881. The reversal of 21108874 is 47880112.

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., 21095649 + 13225 = 4593^2 + 115^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5277217 + ... + 5277220.

Almost surely, 2^21108874 is an apocalyptic number.

21108874 is a deficient number, since it is larger than the sum of its proper divisors (10554440).

21108874 is a wasteful number, since it uses less digits than its factorization.

21108874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10554439.

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 21108874 is about 4594.4394652667. The cubic root of 21108874 is about 276.3683819316.

Adding to 21108874 its reverse (47880112), we get a palindrome (68988986).

It can be divided in two parts, 2110 and 8874, that multiplied together give a triangular number (18724140 = T₆₁₁₉).

The spelling of 21108874 in words is "twenty-one million, one hundred eight thousand, eight hundred seventy-four".