20661760 has 80 divisors (see below), whose sum is σ = 56666016. Its totient is φ = 7077888.

The previous prime is 20661727. The next prime is 20661763. The reversal of 20661760 is 6716602.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661763) 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, 17344 + ... + 18496.

Almost surely, 2^20661760 is an apocalyptic number.

20661760 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 20661760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28333008).

20661760 is an abundant number, since it is smaller than the sum of its proper divisors (36004256).

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

20661760 is an equidigital number, since it uses as much as digits as its factorization.

20661760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183 (or 1167 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 20661760 is about 4545.5208722434. The cubic root of 20661760 is about 274.4031573782.

The spelling of 20661760 in words is "twenty million, six hundred sixty-one thousand, seven hundred sixty".