999729991 has 8 divisors (see below), whose sum is σ = 1078043120. Its totient is φ = 921618432.

The previous prime is 999729989. The next prime is 999730093. The reversal of 999729991 is 199927999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 999729991 - 2¹ = 999729989 is a prime.

It is a Duffinian number.

999729991 is a modest number, since divided by 29991 gives 9997 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999729901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40005 + ... + 59998.

It is an arithmetic number, because the mean of its divisors is an integer number (134755390).

Almost surely, 2^999729991 is an apocalyptic number.

999729991 is a deficient number, since it is larger than the sum of its proper divisors (78313129).

999729991 is a wasteful number, since it uses less digits than its factorization.

999729991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100785.

The product of its digits is 7440174, while the sum is 64.

The square root of 999729991 is about 31618.5070963194. The cubic root of 999729991 is about 999.9099888982.

The spelling of 999729991 in words is "nine hundred ninety-nine million, seven hundred twenty-nine thousand, nine hundred ninety-one".