1309740391 has 4 divisors (see below), whose sum is σ = 1310113192. Its totient is φ = 1309367592.

The previous prime is 1309740379. The next prime is 1309740407. The reversal of 1309740391 is 1930479031.

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

It is a cyclic number.

It is not a de Polignac number, because 1309740391 - 2²³ = 1301351783 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1309740391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1309740361) 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, 181080 + ... + 188173.

It is an arithmetic number, because the mean of its divisors is an integer number (327528298).

Almost surely, 2^1309740391 is an apocalyptic number.

1309740391 is the 20895-th hex number.

1309740391 is a deficient number, since it is larger than the sum of its proper divisors (372801).

1309740391 is an equidigital number, since it uses as much as digits as its factorization.

1309740391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372800.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 1309740391 is about 36190.3356022019. The cubic root of 1309740391 is about 1094.1118966745. Note that the first 3 decimals are identical.

It can be divided in two parts, 1309740 and 391, that added together give a palindrome (1310131).

The spelling of 1309740391 in words is "one billion, three hundred nine million, seven hundred forty thousand, three hundred ninety-one".