1388388806 has 16 divisors (see below), whose sum is σ = 2386485024. Its totient is φ = 593426304.

The previous prime is 1388388779. The next prime is 1388388821. The reversal of 1388388806 is 6088838831.

It is a super-2 number, since 2×1388388806² = 3855246953252211272, which contains 22 as substring.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 127715 + ... + 138158.

It is an arithmetic number, because the mean of its divisors is an integer number (149155314).

Almost surely, 2^1388388806 is an apocalyptic number.

1388388806 is a deficient number, since it is larger than the sum of its proper divisors (998096218).

1388388806 is a wasteful number, since it uses less digits than its factorization.

1388388806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266255.

The product of its (nonzero) digits is 1769472, while the sum is 53.

The square root of 1388388806 is about 37261.0897049456. The cubic root of 1388388806 is about 1115.5876586099.

The spelling of 1388388806 in words is "one billion, three hundred eighty-eight million, three hundred eighty-eight thousand, eight hundred six".