1561331 has 8 divisors (see below), whose sum is σ = 1710720. Its totient is φ = 1418368.

The previous prime is 1561303. The next prime is 1561337. The reversal of 1561331 is 1331651.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1561331 - 2⁶ = 1561267 is a prime.

It is a super-2 number, since 2×1561331² = 4875508983122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561337) 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, 1091 + ... + 2076.

It is an arithmetic number, because the mean of its divisors is an integer number (213840).

2^1561331 is an apocalyptic number.

1561331 is a deficient number, since it is larger than the sum of its proper divisors (149389).

1561331 is a wasteful number, since it uses less digits than its factorization.

1561331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3213.

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

The square root of 1561331 is about 1249.5323125074. The cubic root of 1561331 is about 116.0107748612.

Adding to 1561331 its reverse (1331651), we get a palindrome (2892982).

The spelling of 1561331 in words is "one million, five hundred sixty-one thousand, three hundred thirty-one".