1561131 has 24 divisors (see below), whose sum is σ = 2651376. Its totient is φ = 872640.

The previous prime is 1561123. The next prime is 1561139. The reversal of 1561131 is 1311651.

It is an interprime number because it is at equal distance from previous prime (1561123) and next prime (1561139).

It is not a de Polignac number, because 1561131 - 2³ = 1561123 is a prime.

It is a super-2 number, since 2×1561131² = 4874259998322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1561139) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 681 + ... + 1893.

It is an arithmetic number, because the mean of its divisors is an integer number (110474).

2^1561131 is an apocalyptic number.

1561131 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1561131 is a deficient number, since it is larger than the sum of its proper divisors (1090245).

1561131 is a wasteful number, since it uses less digits than its factorization.

1561131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1243 (or 1240 counting only the distinct ones).

The product of its digits is 90, while the sum is 18.

The square root of 1561131 is about 1249.4522800011. The cubic root of 1561131 is about 116.0058211506.

Adding to 1561131 its reverse (1311651), we get a palindrome (2872782).

The spelling of 1561131 in words is "one million, five hundred sixty-one thousand, one hundred thirty-one".