1311971 has 2 divisors, whose sum is σ = 1311972. Its totient is φ = 1311970.

The previous prime is 1311967. The next prime is 1311991. The reversal of 1311971 is 1791131.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1311971 - 2² = 1311967 is a prime.

It is an Ulam number.

It is equal to p₁₀₀₈₇₇ and since 1311971 and 100877 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (1311901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655985 + 655986.

It is an arithmetic number, because the mean of its divisors is an integer number (655986).

2^1311971 is an apocalyptic number.

1311971 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311971 is an equidigital number, since it uses as much as digits as its factorization.

1311971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189, while the sum is 23.

The square root of 1311971 is about 1145.4130259430. The cubic root of 1311971 is about 109.4732668975.

The spelling of 1311971 in words is "one million, three hundred eleven thousand, nine hundred seventy-one".