161618426561 has 8 divisors (see below), whose sum is σ = 167481083904. Its totient is φ = 155796341760.

The previous prime is 161618426549. The next prime is 161618426579. The reversal of 161618426561 is 165624816161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161618426561 - 2¹⁸ = 161618164417 is a prime.

It is a super-2 number, since 2×161618426561² (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 (161618426521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10135025 + ... + 10150958.

It is an arithmetic number, because the mean of its divisors is an integer number (20935135488).

Almost surely, 2^161618426561 is an apocalyptic number.

It is an amenable number.

161618426561 is a deficient number, since it is larger than the sum of its proper divisors (5862657343).

161618426561 is a wasteful number, since it uses less digits than its factorization.

161618426561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20286271.

The product of its digits is 414720, while the sum is 47.

The spelling of 161618426561 in words is "one hundred sixty-one billion, six hundred eighteen million, four hundred twenty-six thousand, five hundred sixty-one".