1531391 has 6 divisors (see below), whose sum is σ = 1571376. Its totient is φ = 1492400.

The previous prime is 1531379. The next prime is 1531447. The reversal of 1531391 is 1931351.

It is a de Polignac number, because none of the positive numbers 2^k-1531391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1531331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1226 + ... + 2136.

It is an arithmetic number, because the mean of its divisors is an integer number (261896).

2^1531391 is an apocalyptic number.

1531391 is a deficient number, since it is larger than the sum of its proper divisors (39985).

1531391 is an frugal number, since it uses more digits than its factorization.

1531391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993 (or 952 counting only the distinct ones).

The product of its digits is 405, while the sum is 23.

The square root of 1531391 is about 1237.4938383685. The cubic root of 1531391 is about 115.2644449971.

The spelling of 1531391 in words is "one million, five hundred thirty-one thousand, three hundred ninety-one".