921749 has 2 divisors, whose sum is σ = 921750. Its totient is φ = 921748.

The previous prime is 921743. The next prime is 921751. The reversal of 921749 is 947129.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 874225 + 47524 = 935^2 + 218^2 .

It is an emirp because it is prime and its reverse (947129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921749 - 2⁴ = 921733 is a prime.

Together with 921751, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460874 + 460875.

It is an arithmetic number, because the mean of its divisors is an integer number (460875).

2⁹²¹⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

921749 is a deficient number, since it is larger than the sum of its proper divisors (1).

921749 is an equidigital number, since it uses as much as digits as its factorization.

921749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 32.

The square root of 921749 is about 960.0776010303. The cubic root of 921749 is about 97.3204761379.

The spelling of 921749 in words is "nine hundred twenty-one thousand, seven hundred forty-nine".