1381729 has 4 divisors (see below), whose sum is σ = 1384084. Its totient is φ = 1379376.

The previous prime is 1381727. The next prime is 1381739. The reversal of 1381729 is 9271831.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9271831 = 47 ⋅197273.

It can be written as a sum of positive squares in 2 ways, for example, as 483025 + 898704 = 695^2 + 948^2 .

It is a cyclic number.

It is not a de Polignac number, because 1381729 - 2¹ = 1381727 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 1381729.

It is not an unprimeable number, because it can be changed into a prime (1381727) 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, 499 + ... + 1735.

It is an arithmetic number, because the mean of its divisors is an integer number (346021).

2^1381729 is an apocalyptic number.

It is an amenable number.

1381729 is a deficient number, since it is larger than the sum of its proper divisors (2355).

1381729 is a wasteful number, since it uses less digits than its factorization.

1381729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2354.

The product of its digits is 3024, while the sum is 31.

The square root of 1381729 is about 1175.4696933567. The cubic root of 1381729 is about 111.3801053276.

The spelling of 1381729 in words is "one million, three hundred eighty-one thousand, seven hundred twenty-nine".