9939905 has 4 divisors (see below), whose sum is σ = 11927892. Its totient is φ = 7951920.

The previous prime is 9939901. The next prime is 9939911. The reversal of 9939905 is 5099399.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5099399 = 23 ⋅221713.

It can be written as a sum of positive squares in 2 ways, for example, as 1343281 + 8596624 = 1159^2 + 2932^2 .

It is not a de Polignac number, because 9939905 - 2² = 9939901 is a prime.

It is a super-2 number, since 2×9939905² = 197603422818050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9939901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 993986 + ... + 993995.

It is an arithmetic number, because the mean of its divisors is an integer number (2981973).

Almost surely, 2^9939905 is an apocalyptic number.

It is an amenable number.

9939905 is a deficient number, since it is larger than the sum of its proper divisors (1987987).

9939905 is a wasteful number, since it uses less digits than its factorization.

9939905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1987986.

The product of its (nonzero) digits is 98415, while the sum is 44.

The square root of 9939905 is about 3152.7614879657. The cubic root of 9939905 is about 215.0110324247.

It can be divided in two parts, 99 and 39905, that added together give a palindrome (40004).

The spelling of 9939905 in words is "nine million, nine hundred thirty-nine thousand, nine hundred five".