9915861 has 4 divisors (see below), whose sum is σ = 13221152. Its totient is φ = 6610572.

The previous prime is 9915859. The next prime is 9915881. The reversal of 9915861 is 1685199.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1685199 = 3 ⋅561733.

It is not a de Polignac number, because 9915861 - 2¹ = 9915859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9915821) 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, 1652641 + ... + 1652646.

It is an arithmetic number, because the mean of its divisors is an integer number (3305288).

Almost surely, 2^9915861 is an apocalyptic number.

It is an amenable number.

9915861 is a deficient number, since it is larger than the sum of its proper divisors (3305291).

9915861 is a wasteful number, since it uses less digits than its factorization.

9915861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3305290.

The product of its digits is 19440, while the sum is 39.

The square root of 9915861 is about 3148.9460141451. The cubic root of 9915861 is about 214.8375264308.

The spelling of 9915861 in words is "nine million, nine hundred fifteen thousand, eight hundred sixty-one".