99719999 has 4 divisors (see below), whose sum is σ = 104968440. Its totient is φ = 94471560.

The previous prime is 99719989. The next prime is 99720001. The reversal of 99719999 is 99991799.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99991799 = 127 ⋅787337.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99719999 is a prime.

It is a Duffinian number.

99719999 is a modest number, since divided by 9999 gives 9971 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99719929) 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, 2624192 + ... + 2624229.

It is an arithmetic number, because the mean of its divisors is an integer number (26242110).

Almost surely, 2^99719999 is an apocalyptic number.

99719999 is a deficient number, since it is larger than the sum of its proper divisors (5248441).

99719999 is a wasteful number, since it uses less digits than its factorization.

99719999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5248440.

The product of its digits is 3720087, while the sum is 62.

The square root of 99719999 is about 9985.9901361858. The cubic root of 99719999 is about 463.7252618893.

The spelling of 99719999 in words is "ninety-nine million, seven hundred nineteen thousand, nine hundred ninety-nine".