1311987 has 8 divisors (see below), whose sum is σ = 1760704. Its totient is φ = 868968.

The previous prime is 1311971. The next prime is 1311991. The reversal of 1311987 is 7891131.

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

It is not a de Polignac number, because 1311987 - 2⁴ = 1311971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1311917) 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, 853 + ... + 1830.

It is an arithmetic number, because the mean of its divisors is an integer number (220088).

2^1311987 is an apocalyptic number.

1311987 is a deficient number, since it is larger than the sum of its proper divisors (448717).

1311987 is a wasteful number, since it uses less digits than its factorization.

1311987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2849.

The product of its digits is 1512, while the sum is 30.

The square root of 1311987 is about 1145.4200103019. The cubic root of 1311987 is about 109.4737119188.

The spelling of 1311987 in words is "one million, three hundred eleven thousand, nine hundred eighty-seven".