66951415961 has 2 divisors, whose sum is σ = 66951415962. Its totient is φ = 66951415960.

The previous prime is 66951415943. The next prime is 66951415981. The reversal of 66951415961 is 16951415966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66767976025 + 183439936 = 258395^2 + 13544^2 .

It is a cyclic number.

It is not a de Polignac number, because 66951415961 - 2⁶ = 66951415897 is a prime.

It is not a weakly prime, because it can be changed into another prime (66951415981) 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, 33475707980 + 33475707981.

It is an arithmetic number, because the mean of its divisors is an integer number (33475707981).

Almost surely, 2^66951415961 is an apocalyptic number.

It is an amenable number.

66951415961 is a deficient number, since it is larger than the sum of its proper divisors (1).

66951415961 is an equidigital number, since it uses as much as digits as its factorization.

66951415961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1749600, while the sum is 53.

The spelling of 66951415961 in words is "sixty-six billion, nine hundred fifty-one million, four hundred fifteen thousand, nine hundred sixty-one".