9990405 has 32 divisors (see below), whose sum is σ = 18184320. Its totient is φ = 5201280.

The previous prime is 9990403. The next prime is 9990457. The reversal of 9990405 is 5040999.

It is not a de Polignac number, because 9990405 - 2¹ = 9990403 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 9990405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9990403) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4945 + ... + 6665.

It is an arithmetic number, because the mean of its divisors is an integer number (568260).

Almost surely, 2^9990405 is an apocalyptic number.

It is an amenable number.

9990405 is a deficient number, since it is larger than the sum of its proper divisors (8193915).

9990405 is a wasteful number, since it uses less digits than its factorization.

9990405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1778 (or 1772 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 9990405 is about 3160.7601933712. The cubic root of 9990405 is about 215.3745409502.

The spelling of 9990405 in words is "nine million, nine hundred ninety thousand, four hundred five".