1305921 has 4 divisors (see below), whose sum is σ = 1741232. Its totient is φ = 870612.

The previous prime is 1305919. The next prime is 1305947. The reversal of 1305921 is 1295031.

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 not a de Polignac number, because 1305921 - 2¹ = 1305919 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1305961) 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, 217651 + ... + 217656.

It is an arithmetic number, because the mean of its divisors is an integer number (435308).

2^1305921 is an apocalyptic number.

It is an amenable number.

1305921 is a deficient number, since it is larger than the sum of its proper divisors (435311).

1305921 is an equidigital number, since it uses as much as digits as its factorization.

1305921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435310.

The product of its (nonzero) digits is 270, while the sum is 21.

The square root of 1305921 is about 1142.7690055300. The cubic root of 1305921 is about 109.3047332077.

The spelling of 1305921 in words is "one million, three hundred five thousand, nine hundred twenty-one".