1390520809 has 4 divisors (see below), whose sum is σ = 1392373120. Its totient is φ = 1388668500.

The previous prime is 1390520801. The next prime is 1390520839. The reversal of 1390520809 is 9080250931.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9080250931 = 271 ⋅33506461.

It is a cyclic number.

It is not a de Polignac number, because 1390520809 - 2³ = 1390520801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1390520801) 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, 925029 + ... + 926530.

It is an arithmetic number, because the mean of its divisors is an integer number (348093280).

Almost surely, 2^1390520809 is an apocalyptic number.

It is an amenable number.

1390520809 is a deficient number, since it is larger than the sum of its proper divisors (1852311).

1390520809 is an equidigital number, since it uses as much as digits as its factorization.

1390520809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1852310.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 1390520809 is about 37289.6877031707. The cubic root of 1390520809 is about 1116.1583968699.

The spelling of 1390520809 in words is "one billion, three hundred ninety million, five hundred twenty thousand, eight hundred nine".