1385991 has 20 divisors (see below), whose sum is σ = 2108304. Its totient is φ = 907200.

The previous prime is 1385987. The next prime is 1386013. The reversal of 1385991 is 1995831.

It is a happy number.

It is not a de Polignac number, because 1385991 - 2² = 1385987 is a prime.

Its product of digits (9720) is a multiple of the sum of its prime factors (324).

1385991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1385921) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 5631 + ... + 5871.

2^1385991 is an apocalyptic number.

1385991 is a deficient number, since it is larger than the sum of its proper divisors (722313).

1385991 is an equidigital number, since it uses as much as digits as its factorization.

1385991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324 (or 315 counting only the distinct ones).

The product of its digits is 9720, while the sum is 36.

The square root of 1385991 is about 1177.2811898608. The cubic root of 1385991 is about 111.4945066234.

The spelling of 1385991 in words is "one million, three hundred eighty-five thousand, nine hundred ninety-one".