99921728 has 28 divisors (see below), whose sum is σ = 200802240. Its totient is φ = 49325952.

The previous prime is 99921727. The next prime is 99921769. The reversal of 99921728 is 82712999.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99921727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4826 + ... + 14937.

Almost surely, 2^99921728 is an apocalyptic number.

It is an amenable number.

99921728 is an abundant number, since it is smaller than the sum of its proper divisors (100880512).

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

99921728 is a wasteful number, since it uses less digits than its factorization.

99921728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19854 (or 19844 counting only the distinct ones).

The product of its digits is 163296, while the sum is 47.

The square root of 99921728 is about 9996.0856338869. The cubic root of 99921728 is about 464.0377496041.

The spelling of 99921728 in words is "ninety-nine million, nine hundred twenty-one thousand, seven hundred twenty-eight".