161606109999973 has 2 divisors, whose sum is σ = 161606109999974. Its totient is φ = 161606109999972.

The previous prime is 161606109999931. The next prime is 161606109999989. The reversal of 161606109999973 is 379999901606161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 149059510074049 + 12546599925924 = 12208993^2 + 3542118^2 .

It is a cyclic number.

It is not a de Polignac number, because 161606109999973 - 2²⁹ = 161605573129061 is a prime.

It is a super-2 number, since 2×161606109999973² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161606109999973.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161606109993973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80803054999986 + 80803054999987.

It is an arithmetic number, because the mean of its divisors is an integer number (80803054999987).

Almost surely, 2^{161606109999973} is an apocalyptic number.

It is an amenable number.

161606109999973 is a deficient number, since it is larger than the sum of its proper divisors (1).

161606109999973 is an equidigital number, since it uses as much as digits as its factorization.

161606109999973 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 267846264, while the sum is 76.

The spelling of 161606109999973 in words is "one hundred sixty-one trillion, six hundred six billion, one hundred nine million, nine hundred ninety-nine thousand, nine hundred seventy-three".