280857217 has 2 divisors, whose sum is σ = 280857218. Its totient is φ = 280857216.

The previous prime is 280857193. The next prime is 280857263. The reversal of 280857217 is 712758082.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 155775361 + 125081856 = 12481^2 + 11184^2 .

It is a cyclic number.

It is not a de Polignac number, because 280857217 - 2¹⁵ = 280824449 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 280857217.

It is not a weakly prime, because it can be changed into another prime (280857277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140428608 + 140428609.

It is an arithmetic number, because the mean of its divisors is an integer number (140428609).

Almost surely, 2^280857217 is an apocalyptic number.

It is an amenable number.

280857217 is a deficient number, since it is larger than the sum of its proper divisors (1).

280857217 is an equidigital number, since it uses as much as digits as its factorization.

280857217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 62720, while the sum is 40.

The square root of 280857217 is about 16758.7952132604. The cubic root of 280857217 is about 654.8802041854.

It can be divided in two parts, 2808 and 57217, that added together give a square (60025 = 245²).

The spelling of 280857217 in words is "two hundred eighty million, eight hundred fifty-seven thousand, two hundred seventeen".