811677661 has 4 divisors (see below), whose sum is σ = 812112892. Its totient is φ = 811242432.

The previous prime is 811677653. The next prime is 811677689. The reversal of 811677661 is 166776118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166776118 = 2 ⋅83388059.

It can be written as a sum of positive squares in 2 ways, for example, as 125552025 + 686125636 = 11205^2 + 26194^2 .

It is a cyclic number.

It is not a de Polignac number, because 811677661 - 2³ = 811677653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811677161) 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, 214806 + ... + 218551.

It is an arithmetic number, because the mean of its divisors is an integer number (203028223).

Almost surely, 2^811677661 is an apocalyptic number.

It is an amenable number.

811677661 is a deficient number, since it is larger than the sum of its proper divisors (435231).

811677661 is a wasteful number, since it uses less digits than its factorization.

811677661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435230.

The product of its digits is 84672, while the sum is 43.

The square root of 811677661 is about 28489.9571954750. The cubic root of 811677661 is about 932.8128737587.

The spelling of 811677661 in words is "eight hundred eleven million, six hundred seventy-seven thousand, six hundred sixty-one".