99997128 has 192 divisors, whose sum is σ = 357851520. Its totient is φ = 24422400.

The previous prime is 99997127. The next prime is 99997129. The reversal of 99997128 is 82179999.

It is an interprime number because it is at equal distance from previous prime (99997127) and next prime (99997129).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99997127) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 93718 + ... + 94778.

It is an arithmetic number, because the mean of its divisors is an integer number (1863810).

Almost surely, 2^99997128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99997128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (178925760).

99997128 is an abundant number, since it is smaller than the sum of its proper divisors (257854392).

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

99997128 is a wasteful number, since it uses less digits than its factorization.

99997128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1108 (or 1101 counting only the distinct ones).

The product of its digits is 734832, while the sum is 54.

The square root of 99997128 is about 9999.8563989689. The cubic root of 99997128 is about 464.1544397710.

It can be divided in two parts, 999971 and 28, that added together give a palindrome (999999).

The spelling of 99997128 in words is "ninety-nine million, nine hundred ninety-seven thousand, one hundred twenty-eight".