1388251257 has 8 divisors (see below), whose sum is σ = 1914829440. Its totient is φ = 893586960.

The previous prime is 1388251231. The next prime is 1388251343. The reversal of 1388251257 is 7521528831.

1388251257 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 1388251257 - 2¹¹ = 1388249209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1388251157) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7978369 + ... + 7978542.

It is an arithmetic number, because the mean of its divisors is an integer number (239353680).

Almost surely, 2^1388251257 is an apocalyptic number.

It is an amenable number.

1388251257 is a deficient number, since it is larger than the sum of its proper divisors (526578183).

1388251257 is a wasteful number, since it uses less digits than its factorization.

1388251257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15956943.

The product of its digits is 134400, while the sum is 42.

The square root of 1388251257 is about 37259.2439134237. The cubic root of 1388251257 is about 1115.5508166163.

The spelling of 1388251257 in words is "one billion, three hundred eighty-eight million, two hundred fifty-one thousand, two hundred fifty-seven".