1216861 has 8 divisors (see below), whose sum is σ = 1281024. Its totient is φ = 1153680.

The previous prime is 1216849. The next prime is 1216867. The reversal of 1216861 is 1686121.

1216861 = T₃ + T₄ + ... + T₁₉₃.

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

It is not a de Polignac number, because 1216861 - 2⁹ = 1216349 is a prime.

It is a Duffinian number.

1216861 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216867) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4255 + ... + 4531.

It is an arithmetic number, because the mean of its divisors is an integer number (160128).

2^1216861 is an apocalyptic number.

It is an amenable number.

1216861 is a deficient number, since it is larger than the sum of its proper divisors (64163).

1216861 is a wasteful number, since it uses less digits than its factorization.

1216861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491.

The product of its digits is 576, while the sum is 25.

The square root of 1216861 is about 1103.1142279927. The cubic root of 1216861 is about 106.7612518236.

The spelling of 1216861 in words is "one million, two hundred sixteen thousand, eight hundred sixty-one".