997649 has 2 divisors, whose sum is σ = 997650. Its totient is φ = 997648.

The previous prime is 997637. The next prime is 997651. The reversal of 997649 is 946799.

997649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 960400 + 37249 = 980^2 + 193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-997649 is a prime.

Together with 997651, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (997609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498824 + 498825.

It is an arithmetic number, because the mean of its divisors is an integer number (498825).

2⁹⁹⁷⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

997649 is a deficient number, since it is larger than the sum of its proper divisors (1).

997649 is an equidigital number, since it uses as much as digits as its factorization.

997649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 44.

The square root of 997649 is about 998.8238082865. The cubic root of 997649 is about 99.9215718397.

The spelling of 997649 in words is "nine hundred ninety-seven thousand, six hundred forty-nine".