167666750821 has 2 divisors, whose sum is σ = 167666750822. Its totient is φ = 167666750820.

The previous prime is 167666750807. The next prime is 167666750851. The reversal of 167666750821 is 128057666761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136910360196 + 30756390625 = 370014^2 + 175375^2 .

It is an emirp because it is prime and its reverse (128057666761) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 167666750821 - 2²⁷ = 167532533093 is a prime.

It is a super-2 number, since 2×167666750821² (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 (167666750851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83833375410 + 83833375411.

It is an arithmetic number, because the mean of its divisors is an integer number (83833375411).

Almost surely, 2^167666750821 is an apocalyptic number.

It is an amenable number.

167666750821 is a deficient number, since it is larger than the sum of its proper divisors (1).

167666750821 is an equidigital number, since it uses as much as digits as its factorization.

167666750821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5080320, while the sum is 55.

The spelling of 167666750821 in words is "one hundred sixty-seven billion, six hundred sixty-six million, seven hundred fifty thousand, eight hundred twenty-one".