9131217661 has 4 divisors (see below), whose sum is σ = 9131859324. Its totient is φ = 9130576000.

The previous prime is 9131217653. The next prime is 9131217709. The reversal of 9131217661 is 1667121319.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1667121319 = 109 ⋅15294691.

It can be written as a sum of positive squares in 2 ways, for example, as 4198262436 + 4932955225 = 64794^2 + 70235^2 .

It is a cyclic number.

It is not a de Polignac number, because 9131217661 - 2³ = 9131217653 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 9131217661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9131817661) 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, 298990 + ... + 328111.

It is an arithmetic number, because the mean of its divisors is an integer number (2282964831).

Almost surely, 2^9131217661 is an apocalyptic number.

It is an amenable number.

9131217661 is a deficient number, since it is larger than the sum of its proper divisors (641663).

9131217661 is a wasteful number, since it uses less digits than its factorization.

9131217661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641662.

The product of its digits is 13608, while the sum is 37.

The square root of 9131217661 is about 95557.4050558093. The cubic root of 9131217661 is about 2090.1441153495.

The spelling of 9131217661 in words is "nine billion, one hundred thirty-one million, two hundred seventeen thousand, six hundred sixty-one".