9998909661 has 8 divisors (see below), whose sum is σ = 14357408800. Its totient is φ = 6153175152.

The previous prime is 9998909659. The next prime is 9998909689. The reversal of 9998909661 is 1669098999.

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

It is not a de Polignac number, because 9998909661 - 2¹ = 9998909659 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 9998909592 and 9998909601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9998905661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128191111 + ... + 128191188.

It is an arithmetic number, because the mean of its divisors is an integer number (1794676100).

Almost surely, 2^9998909661 is an apocalyptic number.

It is an amenable number.

9998909661 is a deficient number, since it is larger than the sum of its proper divisors (4358499139).

9998909661 is a wasteful number, since it uses less digits than its factorization.

9998909661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256382315.

The product of its (nonzero) digits is 17006112, while the sum is 66.

The square root of 9998909661 is about 99994.5481563870. The cubic root of 9998909661 is about 2154.3563850470.

The spelling of 9998909661 in words is "nine billion, nine hundred ninety-eight million, nine hundred nine thousand, six hundred sixty-one".