161556322541 has 4 divisors (see below), whose sum is σ = 161561346912. Its totient is φ = 161551298172.

The previous prime is 161556322523. The next prime is 161556322561. The reversal of 161556322541 is 145223655161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 161556322541 - 2¹⁰ = 161556321517 is a prime.

It is a super-2 number, since 2×161556322541² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161556322561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2463641 + ... + 2528366.

It is an arithmetic number, because the mean of its divisors is an integer number (40390336728).

Almost surely, 2^161556322541 is an apocalyptic number.

It is an amenable number.

161556322541 is a deficient number, since it is larger than the sum of its proper divisors (5024371).

161556322541 is an equidigital number, since it uses as much as digits as its factorization.

161556322541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5024370.

The product of its digits is 216000, while the sum is 41.

The spelling of 161556322541 in words is "one hundred sixty-one billion, five hundred fifty-six million, three hundred twenty-two thousand, five hundred forty-one".