20018550 has 48 divisors (see below), whose sum is σ = 49920912. Its totient is φ = 5308800.

The previous prime is 20018543. The next prime is 20018567. The reversal of 20018550 is 5581002.

It is a congruent number.

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, 47340 + ... + 47760.

It is an arithmetic number, because the mean of its divisors is an integer number (1040019).

Almost surely, 2^20018550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20018550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24960456).

20018550 is an abundant number, since it is smaller than the sum of its proper divisors (29902362).

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

20018550 is a wasteful number, since it uses less digits than its factorization.

20018550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 753 (or 748 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 21.

The square root of 20018550 is about 4474.2094273737. The cubic root of 20018550 is about 271.5256564720.

Adding to 20018550 its reverse (5581002), we get a palindrome (25599552).

The spelling of 20018550 in words is "twenty million, eighteen thousand, five hundred fifty".