1813115531 has 4 divisors (see below), whose sum is σ = 1847325312. Its totient is φ = 1778905752.

The previous prime is 1813115509. The next prime is 1813115543. The reversal of 1813115531 is 1355113181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1355113181 = 41 ⋅33051541.

It is a cyclic number.

It is not a de Polignac number, because 1813115531 - 2¹⁰ = 1813114507 is a prime.

It is a super-2 number, since 2×1813115531² = 6574775857506823922, 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 = 1813115494 and 1813115503.

It is not an unprimeable number, because it can be changed into a prime (1813115581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17104811 + ... + 17104916.

It is an arithmetic number, because the mean of its divisors is an integer number (461831328).

Almost surely, 2^1813115531 is an apocalyptic number.

1813115531 is a deficient number, since it is larger than the sum of its proper divisors (34209781).

1813115531 is an equidigital number, since it uses as much as digits as its factorization.

1813115531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34209780.

The product of its digits is 1800, while the sum is 29.

The square root of 1813115531 is about 42580.6943461471. The cubic root of 1813115531 is about 1219.3877450632.

The spelling of 1813115531 in words is "one billion, eight hundred thirteen million, one hundred fifteen thousand, five hundred thirty-one".