1091612161 has 4 divisors (see below), whose sum is σ = 1091779924. Its totient is φ = 1091444400.

The previous prime is 1091612153. The next prime is 1091612183. The reversal of 1091612161 is 1612161901.

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 689850225 + 401761936 = 26265^2 + 20044^2 .

It is a cyclic number.

It is not a de Polignac number, because 1091612161 - 2³ = 1091612153 is a prime.

It is a super-2 number, since 2×1091612161² = 2383234220086179842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1091612191) 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, 73710 + ... + 87271.

It is an arithmetic number, because the mean of its divisors is an integer number (272944981).

Almost surely, 2^1091612161 is an apocalyptic number.

It is an amenable number.

1091612161 is a deficient number, since it is larger than the sum of its proper divisors (167763).

1091612161 is an equidigital number, since it uses as much as digits as its factorization.

1091612161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167762.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 1091612161 is about 33039.5544915485. The cubic root of 1091612161 is about 1029.6495999158.

The spelling of 1091612161 in words is "one billion, ninety-one million, six hundred twelve thousand, one hundred sixty-one".