99721240 has 32 divisors (see below), whose sum is σ = 225017280. Its totient is φ = 39773952.

The previous prime is 99721231. The next prime is 99721243. The reversal of 99721240 is 4212799.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 99721196 and 99721205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99721243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11284 + ... + 18076.

It is an arithmetic number, because the mean of its divisors is an integer number (7031790).

Almost surely, 2^99721240 is an apocalyptic number.

It is an amenable number.

99721240 is an abundant number, since it is smaller than the sum of its proper divisors (125296040).

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

99721240 is a wasteful number, since it uses less digits than its factorization.

99721240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7171 (or 7167 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 99721240 is about 9986.0522730456. The cubic root of 99721240 is about 463.7271855444.

The spelling of 99721240 in words is "ninety-nine million, seven hundred twenty-one thousand, two hundred forty".