166557663869 has 2 divisors, whose sum is σ = 166557663870. Its totient is φ = 166557663868.

The previous prime is 166557663823. The next prime is 166557663893. The reversal of 166557663869 is 968366755661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 143934495769 + 22623168100 = 379387^2 + 150410^2 .

It is a cyclic number.

It is not a de Polignac number, because 166557663869 - 2³⁶ = 97838187133 is a prime.

It is a super-2 number, since 2×166557663869² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 166557663799 and 166557663808.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166557663269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83278831934 + 83278831935.

It is an arithmetic number, because the mean of its divisors is an integer number (83278831935).

Almost surely, 2^166557663869 is an apocalyptic number.

It is an amenable number.

166557663869 is a deficient number, since it is larger than the sum of its proper divisors (1).

166557663869 is an equidigital number, since it uses as much as digits as its factorization.

166557663869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 293932800, while the sum is 68.

The spelling of 166557663869 in words is "one hundred sixty-six billion, five hundred fifty-seven million, six hundred sixty-three thousand, eight hundred sixty-nine".