1388813257 has 8 divisors (see below), whose sum is σ = 1496726280. Its totient is φ = 1281054720.

The previous prime is 1388813243. The next prime is 1388813267. The reversal of 1388813257 is 7523188831.

It can be written as a sum of positive squares in 4 ways, for example, as 56490256 + 1332323001 = 7516^2 + 36501^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1388813257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1388813267) 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 7 ways as a sum of consecutive naturals, for example, 19594 + ... + 56227.

It is an arithmetic number, because the mean of its divisors is an integer number (187090785).

Almost surely, 2^1388813257 is an apocalyptic number.

It is an amenable number.

1388813257 is a deficient number, since it is larger than the sum of its proper divisors (107913023).

1388813257 is a wasteful number, since it uses less digits than its factorization.

1388813257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77243.

The product of its digits is 322560, while the sum is 46.

The square root of 1388813257 is about 37266.7849029132. The cubic root of 1388813257 is about 1115.7013309113.

The spelling of 1388813257 in words is "one billion, three hundred eighty-eight million, eight hundred thirteen thousand, two hundred fifty-seven".