9651789661 has 16 divisors (see below), whose sum is σ = 10324266480. Its totient is φ = 8991129600.

The previous prime is 9651789649. The next prime is 9651789703. The reversal of 9651789661 is 1669871569.

9651789661 = T₈₀₂₁₄ + T₈₀₂₁₅ + T₈₀₂₁₆.

It can be written as a sum of positive squares in 8 ways, for example, as 1920104761 + 7731684900 = 43819^2 + 87930^2 .

It is a 7-Lehmer number, since φ(9651789661) divides (9651789661-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 9651789661 - 2⁷ = 9651789533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 9651789596 and 9651789605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9651789601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2223285 + ... + 2227621.

It is an arithmetic number, because the mean of its divisors is an integer number (645266655).

Almost surely, 2^9651789661 is an apocalyptic number.

9651789661 is the 80216-th centered triangular number.

It is an amenable number.

9651789661 is a deficient number, since it is larger than the sum of its proper divisors (672476819).

9651789661 is a wasteful number, since it uses less digits than its factorization.

9651789661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5664.

The product of its digits is 4898880, while the sum is 58.

The square root of 9651789661 is about 98243.5222342929. The cubic root of 9651789661 is about 2129.1321422743.

The spelling of 9651789661 in words is "nine billion, six hundred fifty-one million, seven hundred eighty-nine thousand, six hundred sixty-one".