99720540 has 36 divisors (see below), whose sum is σ = 302486184. Its totient is φ = 26592096.

The previous prime is 99720529. The next prime is 99720541. The reversal of 99720540 is 4502799.

99720540 is a `hidden beast` number, since 9 + 97 + 20 + 540 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 99720495 and 99720504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99720541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 276822 + ... + 277181.

It is an arithmetic number, because the mean of its divisors is an integer number (8402394).

Almost surely, 2^99720540 is an apocalyptic number.

99720540 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

99720540 is an abundant number, since it is smaller than the sum of its proper divisors (202765644).

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

99720540 is a wasteful number, since it uses less digits than its factorization.

99720540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554018 (or 554013 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 99720540 is about 9986.0172240989. The cubic root of 99720540 is about 463.7261004871.

The spelling of 99720540 in words is "ninety-nine million, seven hundred twenty thousand, five hundred forty".