1201891 has 4 divisors (see below), whose sum is σ = 1204552. Its totient is φ = 1199232.

The previous prime is 1201873. The next prime is 1201909. The reversal of 1201891 is 1981021.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1201873) and next prime (1201909).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1201891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1201841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 465 + ... + 1618.

It is an arithmetic number, because the mean of its divisors is an integer number (301138).

2^1201891 is an apocalyptic number.

1201891 is a deficient number, since it is larger than the sum of its proper divisors (2661).

1201891 is an equidigital number, since it uses as much as digits as its factorization.

1201891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2660.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 1201891 is about 1096.3078947084. The cubic root of 1201891 is about 106.3216467165.

The spelling of 1201891 in words is "one million, two hundred one thousand, eight hundred ninety-one".