1281638 has 8 divisors (see below), whose sum is σ = 1931160. Its totient is φ = 637920.

The previous prime is 1281587. The next prime is 1281649. The reversal of 1281638 is 8361821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1281638.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 848 + ... + 1811.

It is an arithmetic number, because the mean of its divisors is an integer number (241395).

2^1281638 is an apocalyptic number.

1281638 is a deficient number, since it is larger than the sum of its proper divisors (649522).

1281638 is a wasteful number, since it uses less digits than its factorization.

1281638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2902.

The product of its digits is 2304, while the sum is 29.

The square root of 1281638 is about 1132.0945190222. The cubic root of 1281638 is about 108.6229996723.

The spelling of 1281638 in words is "one million, two hundred eighty-one thousand, six hundred thirty-eight".