99540 has 72 divisors (see below), whose sum is σ = 349440. Its totient is φ = 22464.

The previous prime is 99529. The next prime is 99551. The reversal of 99540 is 4599.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (99529) and next prime (99551).

It is an Ulam number.

It is a nialpdrome in base 10.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 99540.

It is an unprimeable number.

99540 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1221 + ... + 1299.

2⁹⁹⁵⁴⁰ is an apocalyptic number.

99540 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a pronic number, being equal to 315×316.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (174720).

99540 is an abundant number, since it is smaller than the sum of its proper divisors (249900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

99540 is a wasteful number, since it uses less digits than its factorization.

99540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 99540 is about 315.4996038032. The cubic root of 99540 is about 46.3446078987.

It can be divided in two parts, 995 and 40, that added together give a triangular number (1035 = T₄₅).

The spelling of 99540 in words is "ninety-nine thousand, five hundred forty".