921665497 has 2 divisors, whose sum is σ = 921665498. Its totient is φ = 921665496.

The previous prime is 921665447. The next prime is 921665551. The reversal of 921665497 is 794566129.

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., 831111241 + 90554256 = 28829^2 + 9516^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-921665497 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 921665497.

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, 460832748 + 460832749.

It is an arithmetic number, because the mean of its divisors is an integer number (460832749).

Almost surely, 2^921665497 is an apocalyptic number.

It is an amenable number.

921665497 is a deficient number, since it is larger than the sum of its proper divisors (1).

921665497 is an equidigital number, since it uses as much as digits as its factorization.

921665497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480, while the sum is 49.

The square root of 921665497 is about 30358.9442668878. The cubic root of 921665497 is about 973.1753723327.

The spelling of 921665497 in words is "nine hundred twenty-one million, six hundred sixty-five thousand, four hundred ninety-seven".