990971381 has 2 divisors, whose sum is σ = 990971382. Its totient is φ = 990971380.

The previous prime is 990971363. The next prime is 990971437. The reversal of 990971381 is 183179099.

It is a happy number.

990971381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 828000625 + 162970756 = 28775^2 + 12766^2 .

It is an emirp because it is prime and its reverse (183179099) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-990971381 is a prime.

It is a super-2 number, since 2×990971381² = 1964048555922094322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (990971341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495485690 + 495485691.

It is an arithmetic number, because the mean of its divisors is an integer number (495485691).

Almost surely, 2^990971381 is an apocalyptic number.

It is an amenable number.

990971381 is a deficient number, since it is larger than the sum of its proper divisors (1).

990971381 is an equidigital number, since it uses as much as digits as its factorization.

990971381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 122472, while the sum is 47.

The square root of 990971381 is about 31479.6979178645. The cubic root of 990971381 is about 996.9813572984.

The spelling of 990971381 in words is "nine hundred ninety million, nine hundred seventy-one thousand, three hundred eighty-one".