90018020 has 12 divisors (see below), whose sum is σ = 189037884. Its totient is φ = 36007200.

The previous prime is 90018013. The next prime is 90018023. The reversal of 90018020 is 2081009.

It can be written as a sum of positive squares in 2 ways, for example, as 50353216 + 39664804 = 7096^2 + 6298^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 4500901 = 90018020 / (9 + 0 + 0 + 1 + 8 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 90017983 and 90018001.

It is not an unprimeable number, because it can be changed into a prime (90018023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2250431 + ... + 2250470.

It is an arithmetic number, because the mean of its divisors is an integer number (15753157).

Almost surely, 2^90018020 is an apocalyptic number.

It is an amenable number.

90018020 is an abundant number, since it is smaller than the sum of its proper divisors (99019864).

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

90018020 is a wasteful number, since it uses less digits than its factorization.

90018020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4500910 (or 4500908 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 90018020 is about 9487.7826703609. The cubic root of 90018020 is about 448.1703818870.

Adding to 90018020 its reverse (2081009), we get a palindrome (92099029).

The spelling of 90018020 in words is "ninety million, eighteen thousand, twenty".