1286405 has 4 divisors (see below), whose sum is σ = 1543692. Its totient is φ = 1029120.

The previous prime is 1286399. The next prime is 1286419. The reversal of 1286405 is 5046821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 268324 + 1018081 = 518^2 + 1009^2 .

It is not a de Polignac number, because 1286405 - 2⁸ = 1286149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128636 + ... + 128645.

It is an arithmetic number, because the mean of its divisors is an integer number (385923).

2^1286405 is an apocalyptic number.

It is an amenable number.

1286405 is a deficient number, since it is larger than the sum of its proper divisors (257287).

1286405 is an equidigital number, since it uses as much as digits as its factorization.

1286405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257286.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 1286405 is about 1134.1979545035. The cubic root of 1286405 is about 108.7575059777.

It can be divided in two parts, 128 and 6405, that multiplied together give a triangular number (819840 = T₁₂₈₀).

The spelling of 1286405 in words is "one million, two hundred eighty-six thousand, four hundred five".