1001591 has 4 divisors (see below), whose sum is σ = 1003632. Its totient is φ = 999552.

The previous prime is 1001587. The next prime is 1001593. The reversal of 1001591 is 1951001.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1951001 = 13 ⋅150077.

It is a cyclic number.

It is not a de Polignac number, because 1001591 - 2² = 1001587 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 (1001593) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215 + ... + 1431.

It is an arithmetic number, because the mean of its divisors is an integer number (250908).

2^1001591 is an apocalyptic number.

1001591 is a deficient number, since it is larger than the sum of its proper divisors (2041).

1001591 is an equidigital number, since it uses as much as digits as its factorization.

1001591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2040.

The product of its (nonzero) digits is 45, while the sum is 17.

The square root of 1001591 is about 1000.7951838413. The cubic root of 1001591 is about 100.0530052328.

Adding to 1001591 its reverse (1951001), we get a palindrome (2952592).

The spelling of 1001591 in words is "one million, one thousand, five hundred ninety-one".