90009999 has 12 divisors (see below), whose sum is σ = 130330200. Its totient is φ = 59860944.

The previous prime is 90009943. The next prime is 90010001. The reversal of 90009999 is 99990009.

It is not a de Polignac number, because 90009999 - 2¹⁵ = 89977231 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

90009999 is a modest number, since divided by 9999 gives 9000 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90009919) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8164 + ... + 15705.

It is an arithmetic number, because the mean of its divisors is an integer number (10860850).

Almost surely, 2^90009999 is an apocalyptic number.

90009999 is a deficient number, since it is larger than the sum of its proper divisors (40320201).

90009999 is a wasteful number, since it uses less digits than its factorization.

90009999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24294 (or 24291 counting only the distinct ones).

The product of its (nonzero) digits is 59049, while the sum is 45.

The square root of 90009999 is about 9487.3599594408. The cubic root of 90009999 is about 448.1570701767.

The spelling of 90009999 in words is "ninety million, nine thousand, nine hundred ninety-nine".