20981760 has 96 divisors (see below), whose sum is σ = 67223520. Its totient is φ = 5586944.

The previous prime is 20981749. The next prime is 20981767. The reversal of 20981760 is 6718902.

It is a tau number, because it is divible by the number of its divisors (96).

It is a zygodrome in base 4.

It is not an unprimeable number, because it can be changed into a prime (20981767) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30379 + ... + 31061.

It is an arithmetic number, because the mean of its divisors is an integer number (700245).

Almost surely, 2^20981760 is an apocalyptic number.

20981760 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 20981760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33611760).

20981760 is an abundant number, since it is smaller than the sum of its proper divisors (46241760).

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

20981760 is an equidigital number, since it uses as much as digits as its factorization.

20981760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713 (or 693 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 20981760 is about 4580.5851154629. The cubic root of 20981760 is about 275.8125170768.

The spelling of 20981760 in words is "twenty million, nine hundred eighty-one thousand, seven hundred sixty".