65811961 has 2 divisors, whose sum is σ = 65811962. Its totient is φ = 65811960.

The previous prime is 65811931. The next prime is 65811971. The reversal of 65811961 is 16911856.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64722025 + 1089936 = 8045^2 + 1044^2 .

It is a cyclic number.

It is not a de Polignac number, because 65811961 - 2¹³ = 65803769 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 65811961.

It is not a weakly prime, because it can be changed into another prime (65811931) 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, 32905980 + 32905981.

It is an arithmetic number, because the mean of its divisors is an integer number (32905981).

Almost surely, 2^65811961 is an apocalyptic number.

It is an amenable number.

65811961 is a deficient number, since it is larger than the sum of its proper divisors (1).

65811961 is an equidigital number, since it uses as much as digits as its factorization.

65811961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 37.

The square root of 65811961 is about 8112.4571493475. The cubic root of 65811961 is about 403.7398436997.

The spelling of 65811961 in words is "sixty-five million, eight hundred eleven thousand, nine hundred sixty-one".