1216691 has 8 divisors (see below), whose sum is σ = 1410144. Its totient is φ = 1028160.

The previous prime is 1216681. The next prime is 1216693. The reversal of 1216691 is 1966121.

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

It is not a de Polignac number, because 1216691 - 2¹⁴ = 1200307 is a prime.

It is a super-3 number, since 3×1216691³ = 5403338076205882113, which contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1216691.

It is not an unprimeable number, because it can be changed into a prime (1216693) 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, 680 + ... + 1701.

It is an arithmetic number, because the mean of its divisors is an integer number (176268).

2^1216691 is an apocalyptic number.

1216691 is a deficient number, since it is larger than the sum of its proper divisors (193453).

1216691 is an equidigital number, since it uses as much as digits as its factorization.

1216691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2461.

The product of its digits is 648, while the sum is 26.

The square root of 1216691 is about 1103.0371707245. The cubic root of 1216691 is about 106.7562799443.

The spelling of 1216691 in words is "one million, two hundred sixteen thousand, six hundred ninety-one".