20109870 has 160 divisors (see below), whose sum is σ = 61576416. Its totient is φ = 4665600.

The previous prime is 20109863. The next prime is 20109871. The reversal of 20109870 is 7890102.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20109871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 329640 + ... + 329700.

Almost surely, 2^20109870 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20109870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30788208).

20109870 is an abundant number, since it is smaller than the sum of its proper divisors (41466546).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20109870 is a wasteful number, since it uses less digits than its factorization.

20109870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 20109870 is about 4484.4029702960. The cubic root of 20109870 is about 271.9379093424.

20109870 divided by its sum of digits (27) gives a triangular number (744810 = T₁₂₂₀).

Adding to 20109870 its reverse (7890102), we get a palindrome (27999972).

The spelling of 20109870 in words is "twenty million, one hundred nine thousand, eight hundred seventy".