1291816 has 16 divisors (see below), whose sum is σ = 2445300. Its totient is φ = 639744.

The previous prime is 1291799. The next prime is 1291817. The reversal of 1291816 is 6181921.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 894916 + 396900 = 946^2 + 630^2 .

It is not an unprimeable number, because it can be changed into a prime (1291817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190 + ... + 1618.

2^1291816 is an apocalyptic number.

It is an amenable number.

1291816 is a deficient number, since it is larger than the sum of its proper divisors (1153484).

1291816 is a wasteful number, since it uses less digits than its factorization.

1291816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1548 (or 1544 counting only the distinct ones).

The product of its digits is 864, while the sum is 28.

The square root of 1291816 is about 1136.5808374242. The cubic root of 1291816 is about 108.9097814200.

The spelling of 1291816 in words is "one million, two hundred ninety-one thousand, eight hundred sixteen".