20907720 has 128 divisors (see below), whose sum is σ = 70848000. Its totient is φ = 5552064.

The previous prime is 20907709. The next prime is 20907727. The reversal of 20907720 is 2770902.

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 (20907727) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 87361 + ... + 87599.

It is an arithmetic number, because the mean of its divisors is an integer number (553500).

Almost surely, 2^20907720 is an apocalyptic number.

20907720 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 20907720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35424000).

20907720 is an abundant number, since it is smaller than the sum of its proper divisors (49940280).

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

20907720 is an equidigital number, since it uses as much as digits as its factorization.

20907720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 20907720 is about 4572.4960360836. The cubic root of 20907720 is about 275.4877075509.

The spelling of 20907720 in words is "twenty million, nine hundred seven thousand, seven hundred twenty".