1388390690 has 16 divisors (see below), whose sum is σ = 2499872760. Its totient is φ = 555185280.

The previous prime is 1388390681. The next prime is 1388390713. The reversal of 1388390690 is 960938831.

It can be written as a sum of positive squares in 4 ways, for example, as 1326343561 + 62047129 = 36419^2 + 7877^2 .

It is a super-2 number, since 2×1388390690² = 3855257416157352200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15806 + ... + 55014.

Almost surely, 2^1388390690 is an apocalyptic number.

1388390690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1388390690 is a deficient number, since it is larger than the sum of its proper divisors (1111482070).

1388390690 is a wasteful number, since it uses less digits than its factorization.

1388390690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42757.

The product of its (nonzero) digits is 279936, while the sum is 47.

The square root of 1388390690 is about 37261.1149860012. The cubic root of 1388390690 is about 1115.5881632155.

The spelling of 1388390690 in words is "one billion, three hundred eighty-eight million, three hundred ninety thousand, six hundred ninety".