20909120 has 84 divisors (see below), whose sum is σ = 52838604. Its totient is φ = 7879680.

The previous prime is 20909117. The next prime is 20909173. The reversal of 20909120 is 2190902.

It can be written as a sum of positive squares in 2 ways, for example, as 2795584 + 18113536 = 1672^2 + 4256^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 115430 + ... + 115610.

It is an arithmetic number, because the mean of its divisors is an integer number (629031).

Almost surely, 2^20909120 is an apocalyptic number.

20909120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20909120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26419302).

20909120 is an abundant number, since it is smaller than the sum of its proper divisors (31929484).

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

20909120 is a wasteful number, since it uses less digits than its factorization.

20909120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 20909120 is about 4572.6491227734. The cubic root of 20909120 is about 275.4938563830.

The spelling of 20909120 in words is "twenty million, nine hundred nine thousand, one hundred twenty".