990232581 has 16 divisors (see below), whose sum is σ = 1445185280. Its totient is φ = 599382720.

The previous prime is 990232571. The next prime is 990232603. The reversal of 990232581 is 185232099.

It is not a de Polignac number, because 990232581 - 2¹¹ = 990230533 is a prime.

It is a super-2 number, since 2×990232581² = 1961121128947843122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (990232561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205741 + ... + 210498.

It is an arithmetic number, because the mean of its divisors is an integer number (90324080).

Almost surely, 2^990232581 is an apocalyptic number.

It is an amenable number.

990232581 is a deficient number, since it is larger than the sum of its proper divisors (454952699).

990232581 is a wasteful number, since it uses less digits than its factorization.

990232581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416316.

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 990232581 is about 31467.9611827649. The cubic root of 990232581 is about 996.7335354938.

The spelling of 990232581 in words is "nine hundred ninety million, two hundred thirty-two thousand, five hundred eighty-one".