90609999 has 4 divisors (see below), whose sum is σ = 120813336. Its totient is φ = 60406664.

The previous prime is 90609973. The next prime is 90610081. The reversal of 90609999 is 99990609.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 90609999 - 2⁹ = 90609487 is a prime.

90609999 is a modest number, since divided by 9999 gives 9060 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90609599) 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, 15101664 + ... + 15101669.

It is an arithmetic number, because the mean of its divisors is an integer number (30203334).

Almost surely, 2^90609999 is an apocalyptic number.

90609999 is a deficient number, since it is larger than the sum of its proper divisors (30203337).

90609999 is a wasteful number, since it uses less digits than its factorization.

90609999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30203336.

The product of its (nonzero) digits is 354294, while the sum is 51.

The square root of 90609999 is about 9518.9284586029. The cubic root of 90609999 is about 449.1506596725.

The spelling of 90609999 in words is "ninety million, six hundred nine thousand, nine hundred ninety-nine".