1081581961 has 4 divisors (see below), whose sum is σ = 1082120212. Its totient is φ = 1081043712.

The previous prime is 1081581959. The next prime is 1081581989. The reversal of 1081581961 is 1691851801.

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

It can be written as a sum of positive squares in 2 ways, for example, as 868421961 + 213160000 = 29469^2 + 14600^2 .

It is a cyclic number.

It is not a de Polignac number, because 1081581961 - 2¹ = 1081581959 is a prime.

It is a super-3 number, since 3×1081581961³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1081581901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 266100 + ... + 270133.

It is an arithmetic number, because the mean of its divisors is an integer number (270530053).

Almost surely, 2^1081581961 is an apocalyptic number.

It is an amenable number.

1081581961 is a deficient number, since it is larger than the sum of its proper divisors (538251).

1081581961 is an equidigital number, since it uses as much as digits as its factorization.

1081581961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538250.

The product of its (nonzero) digits is 17280, while the sum is 40.

The square root of 1081581961 is about 32887.4134130369. The cubic root of 1081581961 is about 1026.4862708827.

The spelling of 1081581961 in words is "one billion, eighty-one million, five hundred eighty-one thousand, nine hundred sixty-one".