161565615001 has 12 divisors (see below), whose sum is σ = 188188118580. Its totient is φ = 138304696320.

The previous prime is 161565614989. The next prime is 161565615007. The reversal of 161565615001 is 100516565161.

It can be written as a sum of positive squares in 2 ways, for example, as 118250015625 + 43315599376 = 343875^2 + 208124^2 .

It is not a de Polignac number, because 161565615001 - 2²¹ = 161563517849 is a prime.

It is a super-2 number, since 2×161565615001² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161565615007) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2106180 + ... + 2181541.

It is an arithmetic number, because the mean of its divisors is an integer number (15682343215).

Almost surely, 2^161565615001 is an apocalyptic number.

It is an amenable number.

161565615001 is a deficient number, since it is larger than the sum of its proper divisors (26622503579).

161565615001 is an equidigital number, since it uses as much as digits as its factorization.

161565615001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4288504 (or 4288497 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 37.

The spelling of 161565615001 in words is "one hundred sixty-one billion, five hundred sixty-five million, six hundred fifteen thousand, one".