161333870561 has 4 divisors (see below), whose sum is σ = 162323649072. Its totient is φ = 160344092052.

The previous prime is 161333870513. The next prime is 161333870567. The reversal of 161333870561 is 165078333161.

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 161333870561 - 2¹⁰ = 161333869537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161333870567) 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, 494889011 + ... + 494889336.

It is an arithmetic number, because the mean of its divisors is an integer number (40580912268).

Almost surely, 2^161333870561 is an apocalyptic number.

It is an amenable number.

161333870561 is a deficient number, since it is larger than the sum of its proper divisors (989778511).

161333870561 is an equidigital number, since it uses as much as digits as its factorization.

161333870561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 989778510.

The product of its (nonzero) digits is 272160, while the sum is 44.

The spelling of 161333870561 in words is "one hundred sixty-one billion, three hundred thirty-three million, eight hundred seventy thousand, five hundred sixty-one".