20155560 has 64 divisors (see below), whose sum is σ = 61102080. Its totient is φ = 5318400.

The previous prime is 20155547. The next prime is 20155571. The reversal of 20155560 is 6555102.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20155560.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11289 + ... + 12951.

It is an arithmetic number, because the mean of its divisors is an integer number (954720).

Almost surely, 2^20155560 is an apocalyptic number.

20155560 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 20155560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30551040).

20155560 is an abundant number, since it is smaller than the sum of its proper divisors (40946520).

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

20155560 is a wasteful number, since it uses less digits than its factorization.

20155560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1778 (or 1774 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 20155560 is about 4489.4944036049. The cubic root of 20155560 is about 272.1437029007.

The spelling of 20155560 in words is "twenty million, one hundred fifty-five thousand, five hundred sixty".