65197981 has 2 divisors, whose sum is σ = 65197982. Its totient is φ = 65197980.

The previous prime is 65197961. The next prime is 65197999. The reversal of 65197981 is 18979156.

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., 32878756 + 32319225 = 5734^2 + 5685^2 .

It is a cyclic number.

It is not a de Polignac number, because 65197981 - 2⁹ = 65197469 is a prime.

It is a super-2 number, since 2×65197981² = 8501553452952722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65197921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32598990 + 32598991.

It is an arithmetic number, because the mean of its divisors is an integer number (32598991).

Almost surely, 2^65197981 is an apocalyptic number.

It is an amenable number.

65197981 is a deficient number, since it is larger than the sum of its proper divisors (1).

65197981 is an equidigital number, since it uses as much as digits as its factorization.

65197981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 46.

The square root of 65197981 is about 8074.5266734342. The cubic root of 65197981 is about 402.4803812307.

The spelling of 65197981 in words is "sixty-five million, one hundred ninety-seven thousand, nine hundred eighty-one".