990020 has 24 divisors (see below), whose sum is σ = 2116800. Its totient is φ = 388832.

The previous prime is 990013. The next prime is 990023. The reversal of 990020 is 20099.

990020 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 989974 and 990001.

It is not an unprimeable number, because it can be changed into a prime (990023) by changing a digit.

990020 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 761 + ... + 1599.

It is an arithmetic number, because the mean of its divisors is an integer number (88200).

2⁹⁹⁰⁰²⁰ is an apocalyptic number.

It is an amenable number.

990020 is an abundant number, since it is smaller than the sum of its proper divisors (1126780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

990020 is a wasteful number, since it uses less digits than its factorization.

990020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907 (or 905 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 990020 is about 994.9974874340. The cubic root of 990020 is about 99.6662204852. Note that the first 3 decimals are identical.

The spelling of 990020 in words is "nine hundred ninety thousand, twenty".