1388142691 has 4 divisors (see below), whose sum is σ = 1494922912. Its totient is φ = 1281362472.

The previous prime is 1388142689. The next prime is 1388142731. The reversal of 1388142691 is 1962418831.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1388142691 - 2¹ = 1388142689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1388142601) 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, 53390091 + ... + 53390116.

It is an arithmetic number, because the mean of its divisors is an integer number (373730728).

Almost surely, 2^1388142691 is an apocalyptic number.

1388142691 is a deficient number, since it is larger than the sum of its proper divisors (106780221).

1388142691 is a wasteful number, since it uses less digits than its factorization.

1388142691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106780220.

The product of its digits is 82944, while the sum is 43.

The square root of 1388142691 is about 37257.7869847365. The cubic root of 1388142691 is about 1115.5217358942.

The spelling of 1388142691 in words is "one billion, three hundred eighty-eight million, one hundred forty-two thousand, six hundred ninety-one".