1340821 has 4 divisors (see below), whose sum is σ = 1343200. Its totient is φ = 1338444.

The previous prime is 1340803. The next prime is 1340827. The reversal of 1340821 is 1280431.

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 cyclic number.

It is not a de Polignac number, because 1340821 - 2⁵ = 1340789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1340827) 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, 190 + ... + 1648.

It is an arithmetic number, because the mean of its divisors is an integer number (335800).

2^1340821 is an apocalyptic number.

It is an amenable number.

1340821 is a deficient number, since it is larger than the sum of its proper divisors (2379).

1340821 is an equidigital number, since it uses as much as digits as its factorization.

1340821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2378.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 1340821 is about 1157.9382539669. The cubic root of 1340821 is about 110.2698882439.

The spelling of 1340821 in words is "one million, three hundred forty thousand, eight hundred twenty-one".