161157765640 has 16 divisors (see below), whose sum is σ = 362604972780. Its totient is φ = 64463106240.

The previous prime is 161157765607. The next prime is 161157765667. The reversal of 161157765640 is 46567751161.

It can be written as a sum of positive squares in 2 ways, for example, as 146277181444 + 14880584196 = 382462^2 + 121986^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2014472031 + ... + 2014472110.

Almost surely, 2^161157765640 is an apocalyptic number.

161157765640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161157765640 is an abundant number, since it is smaller than the sum of its proper divisors (201447207140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161157765640 is a wasteful number, since it uses less digits than its factorization.

161157765640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4028944152 (or 4028944148 counting only the distinct ones).

The product of its (nonzero) digits is 1058400, while the sum is 49.

The spelling of 161157765640 in words is "one hundred sixty-one billion, one hundred fifty-seven million, seven hundred sixty-five thousand, six hundred forty".