161903563081 has 12 divisors (see below), whose sum is σ = 175672841040. Its totient is φ = 149144988720.

The previous prime is 161903563079. The next prime is 161903563093. The reversal of 161903563081 is 180365309161.

It is a happy number.

It is not a de Polignac number, because 161903563081 - 2¹ = 161903563079 is a prime.

It is a super-2 number, since 2×161903563081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161903563061) 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, 892591 + ... + 1058548.

It is an arithmetic number, because the mean of its divisors is an integer number (14639403420).

Almost surely, 2^161903563081 is an apocalyptic number.

It is an amenable number.

161903563081 is a deficient number, since it is larger than the sum of its proper divisors (13769277959).

161903563081 is a wasteful number, since it uses less digits than its factorization.

161903563081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1951656 (or 1951643 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 43.

The spelling of 161903563081 in words is "one hundred sixty-one billion, nine hundred three million, five hundred sixty-three thousand, eighty-one".