20668560 has 80 divisors (see below), whose sum is σ = 69906240. Its totient is φ = 5009920.

The previous prime is 20668553. The next prime is 20668567. The reversal of 20668560 is 6586602.

It is an interprime number because it is at equal distance from previous prime (20668553) and next prime (20668567).

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 (33).

It is not an unprimeable number, because it can be changed into a prime (20668567) 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, 1275 + ... + 6554.

It is an arithmetic number, because the mean of its divisors is an integer number (873828).

Almost surely, 2^20668560 is an apocalyptic number.

20668560 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 20668560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34953120).

20668560 is an abundant number, since it is smaller than the sum of its proper divisors (49237680).

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

20668560 is a wasteful number, since it uses less digits than its factorization.

20668560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7856 (or 7850 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 20668560 is about 4546.2687997962. The cubic root of 20668560 is about 274.4332570536.

The spelling of 20668560 in words is "twenty million, six hundred sixty-eight thousand, five hundred sixty".