9819661 has 4 divisors (see below), whose sum is σ = 10158300. Its totient is φ = 9481024.

The previous prime is 9819617. The next prime is 9819671. The reversal of 9819661 is 1669189.

9819661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1669189 = 1031 ⋅1619.

It can be written as a sum of positive squares in 2 ways, for example, as 7873636 + 1946025 = 2806^2 + 1395^2 .

It is a cyclic number.

It is not a de Polignac number, because 9819661 - 2⁷ = 9819533 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9819611) 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, 169276 + ... + 169333.

It is an arithmetic number, because the mean of its divisors is an integer number (2539575).

Almost surely, 2^9819661 is an apocalyptic number.

It is an amenable number.

9819661 is a deficient number, since it is larger than the sum of its proper divisors (338639).

9819661 is a wasteful number, since it uses less digits than its factorization.

9819661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338638.

The product of its digits is 23328, while the sum is 40.

The square root of 9819661 is about 3133.6338331081. The cubic root of 9819661 is about 214.1405095224.

The spelling of 9819661 in words is "nine million, eight hundred nineteen thousand, six hundred sixty-one".