1287021 has 4 divisors (see below), whose sum is σ = 1716032. Its totient is φ = 858012.

The previous prime is 1287007. The next prime is 1287047. The reversal of 1287021 is 1207821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-1287021 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 214501 + ... + 214506.

It is an arithmetic number, because the mean of its divisors is an integer number (429008).

2^1287021 is an apocalyptic number.

It is an amenable number.

1287021 is a deficient number, since it is larger than the sum of its proper divisors (429011).

1287021 is an equidigital number, since it uses as much as digits as its factorization.

1287021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429010.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 1287021 is about 1134.4694795366. The cubic root of 1287021 is about 108.7748628581.

The spelling of 1287021 in words is "one million, two hundred eighty-seven thousand, twenty-one".