66978101 has 2 divisors, whose sum is σ = 66978102. Its totient is φ = 66978100.

The previous prime is 66978089. The next prime is 66978127. The reversal of 66978101 is 10187966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39363076 + 27615025 = 6274^2 + 5255^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66978101 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66978701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33489050 + 33489051.

It is an arithmetic number, because the mean of its divisors is an integer number (33489051).

Almost surely, 2^66978101 is an apocalyptic number.

It is an amenable number.

66978101 is a deficient number, since it is larger than the sum of its proper divisors (1).

66978101 is an equidigital number, since it uses as much as digits as its factorization.

66978101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 66978101 is about 8184.0149682170. The cubic root of 66978101 is about 406.1105545550.

The spelling of 66978101 in words is "sixty-six million, nine hundred seventy-eight thousand, one hundred one".