21108890 has 16 divisors (see below), whose sum is σ = 41450400. Its totient is φ = 7675920.

The previous prime is 21108889. The next prime is 21108911. The reversal of 21108890 is 9880112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95840 + ... + 96059.

It is an arithmetic number, because the mean of its divisors is an integer number (2590650).

Almost surely, 2^21108890 is an apocalyptic number.

21108890 is a deficient number, since it is larger than the sum of its proper divisors (20341510).

21108890 is a wasteful number, since it uses less digits than its factorization.

21108890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191917.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 21108890 is about 4594.4412065016. The cubic root of 21108890 is about 276.3684517584.

The spelling of 21108890 in words is "twenty-one million, one hundred eight thousand, eight hundred ninety".