921665447 has 2 divisors, whose sum is σ = 921665448. Its totient is φ = 921665446.

The previous prime is 921665417. The next prime is 921665497. The reversal of 921665447 is 744566129.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 921665447 - 2⁶ = 921665383 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 921665398 and 921665407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921665417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460832723 + 460832724.

It is an arithmetic number, because the mean of its divisors is an integer number (460832724).

Almost surely, 2^921665447 is an apocalyptic number.

921665447 is a deficient number, since it is larger than the sum of its proper divisors (1).

921665447 is an equidigital number, since it uses as much as digits as its factorization.

921665447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 44.

The square root of 921665447 is about 30358.9434434072. The cubic root of 921665447 is about 973.1753547345.

The spelling of 921665447 in words is "nine hundred twenty-one million, six hundred sixty-five thousand, four hundred forty-seven".