1331561 has 8 divisors (see below), whose sum is σ = 1660224. Its totient is φ = 1037520.

The previous prime is 1331549. The next prime is 1331567. The reversal of 1331561 is 1651331.

It is a happy number.

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

It is not a de Polignac number, because 1331561 - 2⁶ = 1331497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1331567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8570 + ... + 8723.

It is an arithmetic number, because the mean of its divisors is an integer number (207528).

2^1331561 is an apocalyptic number.

1331561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1331561 is a deficient number, since it is larger than the sum of its proper divisors (328663).

1331561 is a wasteful number, since it uses less digits than its factorization.

1331561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17311.

The product of its digits is 270, while the sum is 20.

The square root of 1331561 is about 1153.9328403334. The cubic root of 1331561 is about 110.0154523747.

Adding to 1331561 its reverse (1651331), we get a palindrome (2982892).

The spelling of 1331561 in words is "one million, three hundred thirty-one thousand, five hundred sixty-one".