1561118831 has 8 divisors (see below), whose sum is σ = 1643664000. Its totient is φ = 1478611800.

The previous prime is 1561118821. The next prime is 1561118833. The reversal of 1561118831 is 1388111651.

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 1561118831 - 2¹⁰ = 1561117807 is a prime.

It is a super-2 number, since 2×1561118831² = 4874184009005613122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1561118791 and 1561118800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561118833) 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, 119156 + ... + 131606.

It is an arithmetic number, because the mean of its divisors is an integer number (205458000).

Almost surely, 2^1561118831 is an apocalyptic number.

1561118831 is a deficient number, since it is larger than the sum of its proper divisors (82545169).

1561118831 is a wasteful number, since it uses less digits than its factorization.

1561118831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19069.

The product of its digits is 5760, while the sum is 35.

The square root of 1561118831 is about 39510.9963301357. The cubic root of 1561118831 is about 1160.0551972843.

The spelling of 1561118831 in words is "one billion, five hundred sixty-one million, one hundred eighteen thousand, eight hundred thirty-one".