161855615481 has 16 divisors (see below), whose sum is σ = 246719136768. Its totient is φ = 92458170000.

The previous prime is 161855615477. The next prime is 161855615489. The reversal of 161855615481 is 184516558161.

It is not a de Polignac number, because 161855615481 - 2² = 161855615477 is a prime.

It is a super-2 number, since 2×161855615481² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161855615489) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1216645 + ... + 1343106.

It is an arithmetic number, because the mean of its divisors is an integer number (15419946048).

Almost surely, 2^161855615481 is an apocalyptic number.

It is an amenable number.

161855615481 is a deficient number, since it is larger than the sum of its proper divisors (84863521287).

161855615481 is a wasteful number, since it uses less digits than its factorization.

161855615481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2562772.

The product of its digits is 1152000, while the sum is 51.

The spelling of 161855615481 in words is "one hundred sixty-one billion, eight hundred fifty-five million, six hundred fifteen thousand, four hundred eighty-one".