990238309 has 2 divisors, whose sum is σ = 990238310. Its totient is φ = 990238308.

The previous prime is 990238307. The next prime is 990238367. The reversal of 990238309 is 903832099.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 848556900 + 141681409 = 29130^2 + 11903^2 .

It is a cyclic number.

It is not a de Polignac number, because 990238309 - 2¹ = 990238307 is a prime.

It is a super-2 number, since 2×990238309² = 1961143817222358962, which contains 22 as substring.

Together with 990238307, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (990238303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495119154 + 495119155.

It is an arithmetic number, because the mean of its divisors is an integer number (495119155).

Almost surely, 2^990238309 is an apocalyptic number.

It is an amenable number.

990238309 is a deficient number, since it is larger than the sum of its proper divisors (1).

990238309 is an equidigital number, since it uses as much as digits as its factorization.

990238309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 43.

The square root of 990238309 is about 31468.0521958382. The cubic root of 990238309 is about 996.7354573583.

The spelling of 990238309 in words is "nine hundred ninety million, two hundred thirty-eight thousand, three hundred nine".