20280240 has 160 divisors (see below), whose sum is σ = 71870400. Its totient is φ = 5253120.

The previous prime is 20280229. The next prime is 20280259. The reversal of 20280240 is 4208202.

It is a super-2 number, since 2×20280240² = 822576268915200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 88446 + ... + 88674.

It is an arithmetic number, because the mean of its divisors is an integer number (449190).

Almost surely, 2^20280240 is an apocalyptic number.

20280240 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 20280240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35935200).

20280240 is an abundant number, since it is smaller than the sum of its proper divisors (51590160).

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

20280240 is a wasteful number, since it uses less digits than its factorization.

20280240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 20280240 is about 4503.3587465357. The cubic root of 20280240 is about 272.7036997807.

Adding to 20280240 its reverse (4208202), we get a palindrome (24488442).

The spelling of 20280240 in words is "twenty million, two hundred eighty thousand, two hundred forty".