997720049 has 2 divisors, whose sum is σ = 997720050. Its totient is φ = 997720048.

The previous prime is 997720043. The next prime is 997720051. The reversal of 997720049 is 940027799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 511076449 + 486643600 = 22607^2 + 22060^2 .

It is a cyclic number.

It is not a de Polignac number, because 997720049 - 2²⁸ = 729284593 is a prime.

Together with 997720051, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 997719985 and 997720012.

It is not a weakly prime, because it can be changed into another prime (997720043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498860024 + 498860025.

It is an arithmetic number, because the mean of its divisors is an integer number (498860025).

Almost surely, 2^997720049 is an apocalyptic number.

It is an amenable number.

997720049 is a deficient number, since it is larger than the sum of its proper divisors (1).

997720049 is an equidigital number, since it uses as much as digits as its factorization.

997720049 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 285768, while the sum is 47.

The square root of 997720049 is about 31586.7068400617. The cubic root of 997720049 is about 999.2394380255.

The spelling of 997720049 in words is "nine hundred ninety-seven million, seven hundred twenty thousand, forty-nine".