99905 has 16 divisors (see below), whose sum is σ = 136080. Its totient is φ = 69888.

The previous prime is 99901. The next prime is 99907. The reversal of 99905 is 50999.

99905 = 223² + 224².

It can be written as a sum of positive squares in 8 ways, for example, as 1936 + 97969 = 44^2 + 313^2 .

It is not a de Polignac number, because 99905 - 2² = 99901 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99901) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1859 + ... + 1911.

It is an arithmetic number, because the mean of its divisors is an integer number (8505).

2⁹⁹⁹⁰⁵ is an apocalyptic number.

99905 is the 224-th centered square number.

It is an amenable number.

99905 is a deficient number, since it is larger than the sum of its proper divisors (36175).

99905 is a wasteful number, since it uses less digits than its factorization.

99905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100.

The product of its (nonzero) digits is 3645, while the sum is 32.

The square root of 99905 is about 316.0775221366. The cubic root of 99905 is about 46.4011853145.

The spelling of 99905 in words is "ninety-nine thousand, nine hundred five".