1291581 has 6 divisors (see below), whose sum is σ = 1865630. Its totient is φ = 861048.

The previous prime is 1291579. The next prime is 1291603. The reversal of 1291581 is 1851921.

It can be written as a sum of positive squares in only one way, i.e., 1285956 + 5625 = 1134^2 + 75^2 .

It is not a de Polignac number, because 1291581 - 2¹ = 1291579 is a prime.

It is a super-2 number, since 2×1291581² = 3336362959122, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291501) 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 5 ways as a sum of consecutive naturals, for example, 71746 + ... + 71763.

2^1291581 is an apocalyptic number.

It is an amenable number.

1291581 is a deficient number, since it is larger than the sum of its proper divisors (574049).

1291581 is a wasteful number, since it uses less digits than its factorization.

1291581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143515 (or 143512 counting only the distinct ones).

The product of its digits is 720, while the sum is 27.

The square root of 1291581 is about 1136.4774524820. The cubic root of 1291581 is about 108.9031769318.

It can be divided in two parts, 12915 and 81, that added together give a square (12996 = 114²).

The spelling of 1291581 in words is "one million, two hundred ninety-one thousand, five hundred eighty-one".