1321987 has 4 divisors (see below), whose sum is σ = 1333800. Its totient is φ = 1310176.

The previous prime is 1321981. The next prime is 1321997. The reversal of 1321987 is 7891231.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1321987 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5737 + ... + 5962.

It is an arithmetic number, because the mean of its divisors is an integer number (333450).

2^1321987 is an apocalyptic number.

1321987 is a deficient number, since it is larger than the sum of its proper divisors (11813).

1321987 is a wasteful number, since it uses less digits than its factorization.

1321987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11812.

The product of its digits is 3024, while the sum is 31.

The square root of 1321987 is about 1149.7769348878. The cubic root of 1321987 is about 109.7511454263.

The spelling of 1321987 in words is "one million, three hundred twenty-one thousand, nine hundred eighty-seven".