161220181247 has 4 divisors (see below), whose sum is σ = 161232228696. Its totient is φ = 161208133800.

The previous prime is 161220181223. The next prime is 161220181273. The reversal of 161220181247 is 742181022161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161220181247 - 2¹⁸ = 161219919103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161220181847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6003629 + ... + 6030422.

It is an arithmetic number, because the mean of its divisors is an integer number (40308057174).

Almost surely, 2^161220181247 is an apocalyptic number.

161220181247 is a deficient number, since it is larger than the sum of its proper divisors (12047449).

161220181247 is a wasteful number, since it uses less digits than its factorization.

161220181247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12047448.

The product of its (nonzero) digits is 10752, while the sum is 35.

The spelling of 161220181247 in words is "one hundred sixty-one billion, two hundred twenty million, one hundred eighty-one thousand, two hundred forty-seven".