166690979018381 has 2 divisors, whose sum is σ = 166690979018382. Its totient is φ = 166690979018380.

The previous prime is 166690979018359. The next prime is 166690979018383. The reversal of 166690979018381 is 183810979096661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 110018072102500 + 56672906915881 = 10488950^2 + 7528141^2 .

It is a cyclic number.

It is not a de Polignac number, because 166690979018381 - 2³⁴ = 166673799149197 is a prime.

It is a super-2 number, since 2×166690979018381² (a number of 29 digits) contains 22 as substring.

Together with 166690979018383, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 166690979018299 and 166690979018308.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166690979018383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83345489509190 + 83345489509191.

It is an arithmetic number, because the mean of its divisors is an integer number (83345489509191).

Almost surely, 2^{166690979018381} is an apocalyptic number.

It is an amenable number.

166690979018381 is a deficient number, since it is larger than the sum of its proper divisors (1).

166690979018381 is an equidigital number, since it uses as much as digits as its factorization.

166690979018381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 211631616, while the sum is 74.

The spelling of 166690979018381 in words is "one hundred sixty-six trillion, six hundred ninety billion, nine hundred seventy-nine million, eighteen thousand, three hundred eighty-one".