1387709 has 4 divisors (see below), whose sum is σ = 1390620. Its totient is φ = 1384800.

The previous prime is 1387691. The next prime is 1387717. The reversal of 1387709 is 9077831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9077831 = 7 ⋅1296833.

It can be written as a sum of positive squares in 2 ways, for example, as 1162084 + 225625 = 1078^2 + 475^2 .

It is a cyclic number.

It is not a de Polignac number, because 1387709 - 2¹⁶ = 1322173 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 (1387109) 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, 554 + ... + 1755.

It is an arithmetic number, because the mean of its divisors is an integer number (347655).

2^1387709 is an apocalyptic number.

It is an amenable number.

1387709 is a deficient number, since it is larger than the sum of its proper divisors (2911).

1387709 is an equidigital number, since it uses as much as digits as its factorization.

1387709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2910.

The product of its (nonzero) digits is 10584, while the sum is 35.

The square root of 1387709 is about 1178.0106111576. The cubic root of 1387709 is about 111.5405551362.

The spelling of 1387709 in words is "one million, three hundred eighty-seven thousand, seven hundred nine".