161615677081 has 2 divisors, whose sum is σ = 161615677082. Its totient is φ = 161615677080.

The previous prime is 161615677063. The next prime is 161615677121. The reversal of 161615677081 is 180776516161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 143406873481 + 18208803600 = 378691^2 + 134940^2 .

It is a cyclic number.

It is not a de Polignac number, because 161615677081 - 2¹⁹ = 161615152793 is a prime.

It is a super-2 number, since 2×161615677081² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161615677381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80807838540 + 80807838541.

It is an arithmetic number, because the mean of its divisors is an integer number (80807838541).

Almost surely, 2^161615677081 is an apocalyptic number.

It is an amenable number.

161615677081 is a deficient number, since it is larger than the sum of its proper divisors (1).

161615677081 is an equidigital number, since it uses as much as digits as its factorization.

161615677081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 423360, while the sum is 49.

The spelling of 161615677081 in words is "one hundred sixty-one billion, six hundred fifteen million, six hundred seventy-seven thousand, eighty-one".