1216881 has 6 divisors (see below), whose sum is σ = 1757730. Its totient is φ = 811248.

The previous prime is 1216879. The next prime is 1216903. The reversal of 1216881 is 1886121.

It can be written as a sum of positive squares in only one way, i.e., 950625 + 266256 = 975^2 + 516^2 .

It is not a de Polignac number, because 1216881 - 2¹ = 1216879 is a prime.

It is a super-2 number, since 2×1216881² = 2961598736322, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1216841) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67596 + ... + 67613.

It is an arithmetic number, because the mean of its divisors is an integer number (292955).

2^1216881 is an apocalyptic number.

It is an amenable number.

1216881 is a deficient number, since it is larger than the sum of its proper divisors (540849).

1216881 is a wasteful number, since it uses less digits than its factorization.

1216881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135215 (or 135212 counting only the distinct ones).

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

The square root of 1216881 is about 1103.1232931998. The cubic root of 1216881 is about 106.7618367202.

The spelling of 1216881 in words is "one million, two hundred sixteen thousand, eight hundred eighty-one".