9991659 has 8 divisors (see below), whose sum is σ = 13647312. Its totient is φ = 6498560.

The previous prime is 9991649. The next prime is 9991669. The reversal of 9991659 is 9561999.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (9991649) and next prime (9991669).

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

It is a cyclic number.

It is not a de Polignac number, because 9991659 - 2¹⁶ = 9926123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9991649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40494 + ... + 40739.

It is an arithmetic number, because the mean of its divisors is an integer number (1705914).

Almost surely, 2^9991659 is an apocalyptic number.

9991659 is a deficient number, since it is larger than the sum of its proper divisors (3655653).

9991659 is a wasteful number, since it uses less digits than its factorization.

9991659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81277.

The product of its digits is 196830, while the sum is 48.

The square root of 9991659 is about 3160.9585571469. The cubic root of 9991659 is about 215.3835518753.

The spelling of 9991659 in words is "nine million, nine hundred ninety-one thousand, six hundred fifty-nine".