1281663 has 10 divisors (see below), whose sum is σ = 1914704. Its totient is φ = 854388.

The previous prime is 1281653. The next prime is 1281667. The reversal of 1281663 is 3661821.

It is not a de Polignac number, because 1281663 - 2⁸ = 1281407 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281667) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 7831 + ... + 7992.

2^1281663 is an apocalyptic number.

1281663 is a deficient number, since it is larger than the sum of its proper divisors (633041).

1281663 is an equidigital number, since it uses as much as digits as its factorization.

1281663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15835 (or 15826 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 1281663 is about 1132.1055604492. The cubic root of 1281663 is about 108.6237059449.

The spelling of 1281663 in words is "one million, two hundred eighty-one thousand, six hundred sixty-three".