1005661831 has 4 divisors (see below), whose sum is σ = 1007932392. Its totient is φ = 1003391272.

The previous prime is 1005661777. The next prime is 1005661837. The reversal of 1005661831 is 1381665001.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1005661831 - 2¹¹ = 1005659783 is a prime.

It is a super-2 number, since 2×1005661831² = 2022711436660545122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1005661793 and 1005661802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1005661837) 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, 1134616 + ... + 1135501.

It is an arithmetic number, because the mean of its divisors is an integer number (251983098).

Almost surely, 2^1005661831 is an apocalyptic number.

1005661831 is a deficient number, since it is larger than the sum of its proper divisors (2270561).

1005661831 is an equidigital number, since it uses as much as digits as its factorization.

1005661831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2270560.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 1005661831 is about 31712.1716537988. The cubic root of 1005661831 is about 1001.8837263470.

The spelling of 1005661831 in words is "one billion, five million, six hundred sixty-one thousand, eight hundred thirty-one".