90990999 has 16 divisors (see below), whose sum is σ = 147056640. Its totient is φ = 55145880.

The previous prime is 90990997. The next prime is 90991027. The reversal of 90990999 is 99909909.

It is not a de Polignac number, because 90990999 - 2¹ = 90990997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90990997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 152887 + ... + 153480.

It is an arithmetic number, because the mean of its divisors is an integer number (9191040).

Almost surely, 2^90990999 is an apocalyptic number.

90990999 is a gapful number since it is divisible by the number (99) formed by its first and last digit.

90990999 is a deficient number, since it is larger than the sum of its proper divisors (56065641).

90990999 is a wasteful number, since it uses less digits than its factorization.

90990999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306387 (or 306381 counting only the distinct ones).

The product of its (nonzero) digits is 531441, while the sum is 54.

The square root of 90990999 is about 9538.9202219119. The cubic root of 90990999 is about 449.7793140126.

The spelling of 90990999 in words is "ninety million, nine hundred ninety thousand, nine hundred ninety-nine".