20185506 has 48 divisors (see below), whose sum is σ = 48248928. Its totient is φ = 6048000.

The previous prime is 20185499. The next prime is 20185519. The reversal of 20185506 is 60558102.

It is a self number, because there is not a number n which added to its sum of digits gives 20185506.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18681 + ... + 19731.

It is an arithmetic number, because the mean of its divisors is an integer number (1005186).

Almost surely, 2^20185506 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20185506, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24124464).

20185506 is an abundant number, since it is smaller than the sum of its proper divisors (28063422).

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

20185506 is a wasteful number, since it uses less digits than its factorization.

20185506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167 (or 1164 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 20185506 is about 4492.8282851674. The cubic root of 20185506 is about 272.2784148209.

The spelling of 20185506 in words is "twenty million, one hundred eighty-five thousand, five hundred six".