921825991 has 2 divisors, whose sum is σ = 921825992. Its totient is φ = 921825990.

The previous prime is 921825953. The next prime is 921825997. The reversal of 921825991 is 199528129.

It is a strong prime.

It is an emirp because it is prime and its reverse (199528129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921825991 - 2⁹ = 921825479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921825997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460912995 + 460912996.

It is an arithmetic number, because the mean of its divisors is an integer number (460912996).

Almost surely, 2^921825991 is an apocalyptic number.

921825991 is a deficient number, since it is larger than the sum of its proper divisors (1).

921825991 is an equidigital number, since it uses as much as digits as its factorization.

921825991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 46.

The square root of 921825991 is about 30361.5874255613. The cubic root of 921825991 is about 973.2318569408.

The spelling of 921825991 in words is "nine hundred twenty-one million, eight hundred twenty-five thousand, nine hundred ninety-one".