1331581 has 8 divisors (see below), whose sum is σ = 1378080. Its totient is φ = 1285872.

The previous prime is 1331579. The next prime is 1331587. The reversal of 1331581 is 1851331.

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

It is not a de Polignac number, because 1331581 - 2¹ = 1331579 is a prime.

It is a super-2 number, since 2×1331581² = 3546215919122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7350 + ... + 7528.

It is an arithmetic number, because the mean of its divisors is an integer number (172260).

2^1331581 is an apocalyptic number.

It is an amenable number.

1331581 is a deficient number, since it is larger than the sum of its proper divisors (46499).

1331581 is a wasteful number, since it uses less digits than its factorization.

1331581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395.

The product of its digits is 360, while the sum is 22.

The square root of 1331581 is about 1153.9415063165. The cubic root of 1331581 is about 110.0160031813.

The spelling of 1331581 in words is "one million, three hundred thirty-one thousand, five hundred eighty-one".