97720657 has 2 divisors, whose sum is σ = 97720658. Its totient is φ = 97720656.

The previous prime is 97720627. The next prime is 97720669. The reversal of 97720657 is 75602779.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64496961 + 33223696 = 8031^2 + 5764^2 .

It is a cyclic number.

It is not a de Polignac number, because 97720657 - 2¹⁹ = 97196369 is a prime.

It is a super-5 number, since 5×97720657⁵ (a number of 41 digits) contains 55555 as substring.

It is not a weakly prime, because it can be changed into another prime (97720627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 48860328 + 48860329.

It is an arithmetic number, because the mean of its divisors is an integer number (48860329).

Almost surely, 2^97720657 is an apocalyptic number.

It is an amenable number.

97720657 is a deficient number, since it is larger than the sum of its proper divisors (1).

97720657 is an equidigital number, since it uses as much as digits as its factorization.

97720657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 185220, while the sum is 43.

The square root of 97720657 is about 9885.3759159680. The cubic root of 97720657 is about 460.6051534462.

The spelling of 97720657 in words is "ninety-seven million, seven hundred twenty thousand, six hundred fifty-seven".