99990138 has 8 divisors (see below), whose sum is σ = 199980288. Its totient is φ = 33330044.

The previous prime is 99990113. The next prime is 99990139. The reversal of 99990138 is 83109999.

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

99990138 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (99990139) 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, 8332506 + ... + 8332517.

It is an arithmetic number, because the mean of its divisors is an integer number (24997536).

Almost surely, 2^99990138 is an apocalyptic number.

99990138 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

99990138 is a wasteful number, since it uses less digits than its factorization.

99990138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16665028.

The product of its (nonzero) digits is 157464, while the sum is 48.

The square root of 99990138 is about 9999.5068878420. The cubic root of 99990138 is about 464.1436244100.

It can be divided in two parts, 99990 and 138, that added together give a triangular number (100128 = T₄₄₇).

The spelling of 99990138 in words is "ninety-nine million, nine hundred ninety thousand, one hundred thirty-eight".