1388991 has 8 divisors (see below), whose sum is σ = 1891584. Its totient is φ = 906200.

The previous prime is 1388969. The next prime is 1389001. The reversal of 1388991 is 1998831.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1388991 - 2⁶ = 1388927 is a prime.

It is a super-3 number, since 3×1388991³ = 8039324333011578813, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1388941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4785 + ... + 5066.

It is an arithmetic number, because the mean of its divisors is an integer number (236448).

2^1388991 is an apocalyptic number.

1388991 is a deficient number, since it is larger than the sum of its proper divisors (502593).

1388991 is an equidigital number, since it uses as much as digits as its factorization.

1388991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9901.

The product of its digits is 15552, while the sum is 39.

The square root of 1388991 is about 1178.5546232568. The cubic root of 1388991 is about 111.5748925417.

The spelling of 1388991 in words is "one million, three hundred eighty-eight thousand, nine hundred ninety-one".