166641502381 has 2 divisors, whose sum is σ = 166641502382. Its totient is φ = 166641502380.

The previous prime is 166641502361. The next prime is 166641502421. The reversal of 166641502381 is 183205146661.

166641502381 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., 163838752900 + 2802749481 = 404770^2 + 52941^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166641502381 is a prime.

It is a super-2 number, since 2×166641502381² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166641502301) 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, 83320751190 + 83320751191.

It is an arithmetic number, because the mean of its divisors is an integer number (83320751191).

Almost surely, 2^166641502381 is an apocalyptic number.

It is an amenable number.

166641502381 is a deficient number, since it is larger than the sum of its proper divisors (1).

166641502381 is an equidigital number, since it uses as much as digits as its factorization.

166641502381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 43.

The spelling of 166641502381 in words is "one hundred sixty-six billion, six hundred forty-one million, five hundred two thousand, three hundred eighty-one".