999999138 has 16 divisors (see below), whose sum is σ = 2003031936. Its totient is φ = 332827440.

The previous prime is 999999137. The next prime is 999999151. The reversal of 999999138 is 831999999.

It is not an unprimeable number, because it can be changed into a prime (999999131) 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, 122106 + ... + 130037.

It is an arithmetic number, because the mean of its divisors is an integer number (125189496).

Almost surely, 2^999999138 is an apocalyptic number.

999999138 is an abundant number, since it is smaller than the sum of its proper divisors (1003032798).

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

999999138 is a wasteful number, since it uses less digits than its factorization.

999999138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252809.

The product of its digits is 12754584, while the sum is 66.

The square root of 999999138 is about 31622.7629722641. The cubic root of 999999138 is about 999.9997126666. Note that the first 3 decimals are identical.

The spelling of 999999138 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, one hundred thirty-eight".