161942581867879 has 4 divisors (see below), whose sum is σ = 161944265376400. Its totient is φ = 161940898359360.

The previous prime is 161942581867837. The next prime is 161942581867883. The reversal of 161942581867879 is 978768185249161.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161942581867879 is a prime.

It is a super-2 number, since 2×161942581867879² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161942581867819) 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, 841609962 + ... + 841802359.

It is an arithmetic number, because the mean of its divisors is an integer number (40486066344100).

Almost surely, 2^{161942581867879} is an apocalyptic number.

161942581867879 is a deficient number, since it is larger than the sum of its proper divisors (1683508521).

161942581867879 is an equidigital number, since it uses as much as digits as its factorization.

161942581867879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1683508520.

The product of its digits is 2926264320, while the sum is 82.

The spelling of 161942581867879 in words is "one hundred sixty-one trillion, nine hundred forty-two billion, five hundred eighty-one million, eight hundred sixty-seven thousand, eight hundred seventy-nine".