921491 has 2 divisors, whose sum is σ = 921492. Its totient is φ = 921490.

The previous prime is 921467. The next prime is 921497. The reversal of 921491 is 194129.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 921491 - 2¹⁰ = 920467 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 921491.

It is not a weakly prime, because it can be changed into another prime (921497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460745 + 460746.

It is an arithmetic number, because the mean of its divisors is an integer number (460746).

2⁹²¹⁴⁹¹ is an apocalyptic number.

921491 is a deficient number, since it is larger than the sum of its proper divisors (1).

921491 is an equidigital number, since it uses as much as digits as its factorization.

921491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 26.

The square root of 921491 is about 959.9432274880. The cubic root of 921491 is about 97.3113952037.

The spelling of 921491 in words is "nine hundred twenty-one thousand, four hundred ninety-one".