20109890 has 16 divisors (see below), whose sum is σ = 36968832. Its totient is φ = 7872624.

The previous prime is 20109883. The next prime is 20109893. The reversal of 20109890 is 9890102.

20109890 is a modest number, since divided by 109890 gives 20 as remainder.

It is not an unprimeable number, because it can be changed into a prime (20109893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20924 + ... + 21863.

It is an arithmetic number, because the mean of its divisors is an integer number (2310552).

Almost surely, 2^20109890 is an apocalyptic number.

20109890 is a deficient number, since it is larger than the sum of its proper divisors (16858942).

20109890 is a wasteful number, since it uses less digits than its factorization.

20109890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42841.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 20109890 is about 4484.4052002467. The cubic root of 20109890 is about 271.9379994931.

Adding to 20109890 its reverse (9890102), we get a palindrome (29999992).

The spelling of 20109890 in words is "twenty million, one hundred nine thousand, eight hundred ninety".