280555261 has 4 divisors (see below), whose sum is σ = 320634592. Its totient is φ = 240475932.

The previous prime is 280555243. The next prime is 280555271. The reversal of 280555261 is 162555082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162555082 = 2 ⋅81277541.

It is a cyclic number.

It is not a de Polignac number, because 280555261 - 2²¹ = 278458109 is a prime.

It is a super-2 number, since 2×280555261² = 157422508949556242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (280555241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20039655 + ... + 20039668.

It is an arithmetic number, because the mean of its divisors is an integer number (80158648).

Almost surely, 2^280555261 is an apocalyptic number.

It is an amenable number.

280555261 is a deficient number, since it is larger than the sum of its proper divisors (40079331).

280555261 is an equidigital number, since it uses as much as digits as its factorization.

280555261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40079330.

The product of its (nonzero) digits is 24000, while the sum is 34.

The square root of 280555261 is about 16749.7839090539. The cubic root of 280555261 is about 654.6454278126.

The spelling of 280555261 in words is "two hundred eighty million, five hundred fifty-five thousand, two hundred sixty-one".