66996961 has 2 divisors, whose sum is σ = 66996962. Its totient is φ = 66996960.

The previous prime is 66996947. The next prime is 66996997. The reversal of 66996961 is 16969966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58982400 + 8014561 = 7680^2 + 2831^2 .

It is a cyclic number.

It is not a de Polignac number, because 66996961 - 2¹³ = 66988769 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66996899 and 66996908.

It is not a weakly prime, because it can be changed into another prime (66996161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33498480 + 33498481.

It is an arithmetic number, because the mean of its divisors is an integer number (33498481).

Almost surely, 2^66996961 is an apocalyptic number.

It is an amenable number.

66996961 is a deficient number, since it is larger than the sum of its proper divisors (1).

66996961 is an equidigital number, since it uses as much as digits as its factorization.

66996961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 944784, while the sum is 52.

The square root of 66996961 is about 8185.1671332967. The cubic root of 66996961 is about 406.1486691335.

The spelling of 66996961 in words is "sixty-six million, nine hundred ninety-six thousand, nine hundred sixty-one".