99999540 has 72 divisors (see below), whose sum is σ = 313808040. Its totient is φ = 25745664.

The previous prime is 99999539. The next prime is 99999541. The reversal of 99999540 is 4599999.

It is a happy number.

99999540 is a `hidden beast` number, since 9 + 9 + 9 + 99 + 540 = 666.

It is an interprime number because it is at equal distance from previous prime (99999539) and next prime (99999541).

It can be written as a sum of positive squares in 4 ways, for example, as 79524 + 99920016 = 282^2 + 9996^2 .

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4359 + ... + 14798.

It is an arithmetic number, because the mean of its divisors is an integer number (4358445).

Almost surely, 2^99999540 is an apocalyptic number.

99999540 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

99999540 is an abundant number, since it is smaller than the sum of its proper divisors (213808500).

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

99999540 is a wasteful number, since it uses less digits than its factorization.

99999540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19201 (or 19196 counting only the distinct ones).

The product of its (nonzero) digits is 1180980, while the sum is 54.

The square root of 99999540 is about 9999.9769999735. The cubic root of 99999540 is about 464.1581716499.

The spelling of 99999540 in words is "ninety-nine million, nine hundred ninety-nine thousand, five hundred forty".