161566012227251 has 2 divisors, whose sum is σ = 161566012227252. Its totient is φ = 161566012227250.

The previous prime is 161566012227241. The next prime is 161566012227343. The reversal of 161566012227251 is 152722210665161.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161566012227251 is a prime.

It is a super-2 number, since 2×161566012227251² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161566012227196 and 161566012227205.

It is not a weakly prime, because it can be changed into another prime (161566012227241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80783006113625 + 80783006113626.

It is an arithmetic number, because the mean of its divisors is an integer number (80783006113626).

Almost surely, 2^{161566012227251} is an apocalyptic number.

161566012227251 is a deficient number, since it is larger than the sum of its proper divisors (1).

161566012227251 is an equidigital number, since it uses as much as digits as its factorization.

161566012227251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 604800, while the sum is 47.

The spelling of 161566012227251 in words is "one hundred sixty-one trillion, five hundred sixty-six billion, twelve million, two hundred twenty-seven thousand, two hundred fifty-one".