1281816 has 48 divisors (see below), whose sum is σ = 3658200. Its totient is φ = 404352.

The previous prime is 1281809. The next prime is 1281821. The reversal of 1281816 is 6181821.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1281816.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 900 + ... + 1836.

2^1281816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1281816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1829100).

1281816 is an abundant number, since it is smaller than the sum of its proper divisors (2376384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1281816 is a wasteful number, since it uses less digits than its factorization.

1281816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 968 (or 961 counting only the distinct ones).

The product of its digits is 768, while the sum is 27.

The square root of 1281816 is about 1132.1731316367. The cubic root of 1281816 is about 108.6280281330.

The spelling of 1281816 in words is "one million, two hundred eighty-one thousand, eight hundred sixteen".