1308721 has 4 divisors (see below), whose sum is σ = 1311012. Its totient is φ = 1306432.

The previous prime is 1308719. The next prime is 1308731. The reversal of 1308721 is 1278031.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 518400 + 790321 = 720^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 1308721 - 2¹ = 1308719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1308692 and 1308701.

It is not an unprimeable number, because it can be changed into a prime (1308731) 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, 501 + ... + 1693.

It is an arithmetic number, because the mean of its divisors is an integer number (327753).

2^1308721 is an apocalyptic number.

It is an amenable number.

1308721 is a deficient number, since it is larger than the sum of its proper divisors (2291).

1308721 is a wasteful number, since it uses less digits than its factorization.

1308721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2290.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 1308721 is about 1143.9934440372. The cubic root of 1308721 is about 109.3827968319.

The spelling of 1308721 in words is "one million, three hundred eight thousand, seven hundred twenty-one".