20280018 has 16 divisors (see below), whose sum is σ = 44247456. Its totient is φ = 6145440.

The previous prime is 20280017. The next prime is 20280059. The reversal of 20280018 is 81008202.

It is a super-2 number, since 2×20280018² = 822558260160648, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20279976 and 20280003.

It is not an unprimeable number, because it can be changed into a prime (20280017) 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 7 ways as a sum of consecutive naturals, for example, 153571 + ... + 153702.

It is an arithmetic number, because the mean of its divisors is an integer number (2765466).

Almost surely, 2^20280018 is an apocalyptic number.

20280018 is an abundant number, since it is smaller than the sum of its proper divisors (23967438).

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

20280018 is a wasteful number, since it uses less digits than its factorization.

20280018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307289.

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 20280018 is about 4503.3340981988. The cubic root of 20280018 is about 272.7027047162.

The spelling of 20280018 in words is "twenty million, two hundred eighty thousand, eighteen".