811091661 has 8 divisors (see below), whose sum is σ = 1081657920. Its totient is φ = 540626592.

The previous prime is 811091647. The next prime is 811091663. The reversal of 811091661 is 166190118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 811091661 - 2¹⁵ = 811058893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811091663) 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 7 ways as a sum of consecutive naturals, for example, 4041 + ... + 40478.

It is an arithmetic number, because the mean of its divisors is an integer number (135207240).

Almost surely, 2^811091661 is an apocalyptic number.

It is an amenable number.

811091661 is a deficient number, since it is larger than the sum of its proper divisors (270566259).

811091661 is a wasteful number, since it uses less digits than its factorization.

811091661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50595.

The product of its (nonzero) digits is 2592, while the sum is 33.

The square root of 811091661 is about 28479.6710128470. The cubic root of 811091661 is about 932.5883347283.

The spelling of 811091661 in words is "eight hundred eleven million, ninety-one thousand, six hundred sixty-one".