1385551729 has 3 divisors (see below), whose sum is σ = 1385588953. Its totient is φ = 1385514506.

The previous prime is 1385551711. The next prime is 1385551751. The reversal of 1385551729 is 9271555831.

The square root of 1385551729 is 37223.

It is a perfect power (a square), and thus also a powerful number.

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: 9271555831 = 19963 ⋅464437.

It is a de Polignac number, because none of the positive numbers 2^k-1385551729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1385521729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 18612 + ... + 55834.

Almost surely, 2^1385551729 is an apocalyptic number.

1385551729 is the 37223-rd square number.

1385551729 is the 18612-nd centered octagonal number.

It is an amenable number.

1385551729 is a deficient number, since it is larger than the sum of its proper divisors (37224).

1385551729 is an frugal number, since it uses more digits than its factorization.

1385551729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74446 (or 37223 counting only the distinct ones).

The product of its digits is 378000, while the sum is 46.

The cubic root of 1385551729 is about 1114.8272648955.

The spelling of 1385551729 in words is "one billion, three hundred eighty-five million, five hundred fifty-one thousand, seven hundred twenty-nine".