923647981 has 2 divisors, whose sum is σ = 923647982. Its totient is φ = 923647980.

The previous prime is 923647979. The next prime is 923648003. The reversal of 923647981 is 189746329.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 785961225 + 137686756 = 28035^2 + 11734^2 .

It is an emirp because it is prime and its reverse (189746329) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 923647981 - 2¹ = 923647979 is a prime.

It is a super-2 number, since 2×923647981² = 1706251185610752722, which contains 22 as substring.

Together with 923647979, 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 (923642981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 461823990 + 461823991.

It is an arithmetic number, because the mean of its divisors is an integer number (461823991).

Almost surely, 2^923647981 is an apocalyptic number.

It is an amenable number.

923647981 is a deficient number, since it is larger than the sum of its proper divisors (1).

923647981 is an equidigital number, since it uses as much as digits as its factorization.

923647981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 49.

The square root of 923647981 is about 30391.5774681078. The cubic root of 923647981 is about 973.8726328765.

The spelling of 923647981 in words is "nine hundred twenty-three million, six hundred forty-seven thousand, nine hundred eighty-one".