1213891 has 8 divisors (see below), whose sum is σ = 1460480. Its totient is φ = 985608.

The previous prime is 1213879. The next prime is 1213897. The reversal of 1213891 is 1983121.

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

It is a cyclic number.

It is not a de Polignac number, because 1213891 - 2⁷ = 1213763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1213897) 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, 4431 + ... + 4696.

It is an arithmetic number, because the mean of its divisors is an integer number (182560).

2^1213891 is an apocalyptic number.

1213891 is a deficient number, since it is larger than the sum of its proper divisors (246589).

1213891 is an equidigital number, since it uses as much as digits as its factorization.

1213891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9153.

The product of its digits is 432, while the sum is 25.

The square root of 1213891 is about 1101.7672167931. The cubic root of 1213891 is about 106.6743234521.

The spelling of 1213891 in words is "one million, two hundred thirteen thousand, eight hundred ninety-one".