20185720 has 64 divisors (see below), whose sum is σ = 48755520. Its totient is φ = 7501824.

The previous prime is 20185709. The next prime is 20185723. The reversal of 20185720 is 2758102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20185723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33744 + ... + 34336.

It is an arithmetic number, because the mean of its divisors is an integer number (761805).

Almost surely, 2^20185720 is an apocalyptic number.

20185720 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 20185720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24377760).

20185720 is an abundant number, since it is smaller than the sum of its proper divisors (28569800).

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

20185720 is a wasteful number, since it uses less digits than its factorization.

20185720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 20185720 is about 4492.8521008375. The cubic root of 20185720 is about 272.2793770192.

The spelling of 20185720 in words is "twenty million, one hundred eighty-five thousand, seven hundred twenty".