1997942897 has 2 divisors, whose sum is σ = 1997942898. Its totient is φ = 1997942896.

The previous prime is 1997942887. The next prime is 1997942899. The reversal of 1997942897 is 7982497991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1954435681 + 43507216 = 44209^2 + 6596^2 .

It is a cyclic number.

It is not a de Polignac number, because 1997942897 - 2¹⁶ = 1997877361 is a prime.

Together with 1997942899, 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 (1997942899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998971448 + 998971449.

It is an arithmetic number, because the mean of its divisors is an integer number (998971449).

Almost surely, 2^1997942897 is an apocalyptic number.

It is an amenable number.

1997942897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997942897 is an equidigital number, since it uses as much as digits as its factorization.

1997942897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20575296, while the sum is 65.

The square root of 1997942897 is about 44698.3545222864. The cubic root of 1997942897 is about 1259.4889371490.

The spelling of 1997942897 in words is "one billion, nine hundred ninety-seven million, nine hundred forty-two thousand, eight hundred ninety-seven".