280505640 has 32 divisors (see below), whose sum is σ = 841517280. Its totient is φ = 74801472.

The previous prime is 280505629. The next prime is 280505651. The reversal of 280505640 is 46505082.

It is an interprime number because it is at equal distance from previous prime (280505629) and next prime (280505651).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 280505598 and 280505607.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1168654 + ... + 1168893.

It is an arithmetic number, because the mean of its divisors is an integer number (26297415).

Almost surely, 2^280505640 is an apocalyptic number.

280505640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

280505640 is an abundant number, since it is smaller than the sum of its proper divisors (561011640).

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

280505640 is a wasteful number, since it uses less digits than its factorization.

280505640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2337561 (or 2337557 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 280505640 is about 16748.3026005622. The cubic root of 280505640 is about 654.6068304540.

The spelling of 280505640 in words is "two hundred eighty million, five hundred five thousand, six hundred forty".