97975781 has 2 divisors, whose sum is σ = 97975782. Its totient is φ = 97975780.

The previous prime is 97975771. The next prime is 97975789. The reversal of 97975781 is 18757979.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78039556 + 19936225 = 8834^2 + 4465^2 .

It is an emirp because it is prime and its reverse (18757979) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 97975781 - 2¹⁴ = 97959397 is a prime.

It is a super-2 number, since 2×97975781² = 19198507325119922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (97975789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 48987890 + 48987891.

It is an arithmetic number, because the mean of its divisors is an integer number (48987891).

Almost surely, 2^97975781 is an apocalyptic number.

It is an amenable number.

97975781 is a deficient number, since it is larger than the sum of its proper divisors (1).

97975781 is an equidigital number, since it uses as much as digits as its factorization.

97975781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1111320, while the sum is 53.

The square root of 97975781 is about 9898.2716168026. The cubic root of 97975781 is about 461.0056464317.

The spelling of 97975781 in words is "ninety-seven million, nine hundred seventy-five thousand, seven hundred eighty-one".