280555380 has 288 divisors, whose sum is σ = 1061786880. Its totient is φ = 61205760.

The previous prime is 280555351. The next prime is 280555381. The reversal of 280555380 is 83555082.

280555380 is a `hidden beast` number, since 28 + 0 + 5 + 553 + 80 = 666.

It is a super-2 number, since 2×280555380² = 157422642493888800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (280555381) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 608350 + ... + 608810.

It is an arithmetic number, because the mean of its divisors is an integer number (3686760).

Almost surely, 2^280555380 is an apocalyptic number.

280555380 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 280555380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (530893440).

280555380 is an abundant number, since it is smaller than the sum of its proper divisors (781231500).

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

280555380 is a wasteful number, since it uses less digits than its factorization.

280555380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516 (or 501 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 36.

The square root of 280555380 is about 16749.7874613381. The cubic root of 280555380 is about 654.6455203705.

It can be divided in two parts, 2805 and 55380, that added together give a palindrome (58185).

The spelling of 280555380 in words is "two hundred eighty million, five hundred fifty-five thousand, three hundred eighty".