990209621 has 8 divisors (see below), whose sum is σ = 1011626880. Its totient is φ = 969014592.

The previous prime is 990209609. The next prime is 990209723. The reversal of 990209621 is 126902099.

990209621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 990209621 - 2¹⁸ = 989947477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (990209021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46535 + ... + 64388.

It is an arithmetic number, because the mean of its divisors is an integer number (126453360).

Almost surely, 2^990209621 is an apocalyptic number.

It is an amenable number.

990209621 is a deficient number, since it is larger than the sum of its proper divisors (21417259).

990209621 is a wasteful number, since it uses less digits than its factorization.

990209621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111115.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 990209621 is about 31467.5963651500. The cubic root of 990209621 is about 996.7258318562.

The spelling of 990209621 in words is "nine hundred ninety million, two hundred nine thousand, six hundred twenty-one".