61665100181 has 2 divisors, whose sum is σ = 61665100182. Its totient is φ = 61665100180.

The previous prime is 61665100177. The next prime is 61665100253. The reversal of 61665100181 is 18100156616.

61665100181 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54781743025 + 6883357156 = 234055^2 + 82966^2 .

It is a cyclic number.

It is not a de Polignac number, because 61665100181 - 2² = 61665100177 is a prime.

It is a super-2 number, since 2×61665100181² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61665100121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30832550090 + 30832550091.

It is an arithmetic number, because the mean of its divisors is an integer number (30832550091).

Almost surely, 2^61665100181 is an apocalyptic number.

It is an amenable number.

61665100181 is a deficient number, since it is larger than the sum of its proper divisors (1).

61665100181 is an equidigital number, since it uses as much as digits as its factorization.

61665100181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 35.

Adding to 61665100181 its reverse (18100156616), we get a palindrome (79765256797).

The spelling of 61665100181 in words is "sixty-one billion, six hundred sixty-five million, one hundred thousand, one hundred eighty-one".