181081616977 has 4 divisors (see below), whose sum is σ = 182128331700. Its totient is φ = 180034902256.

The previous prime is 181081616959. The next prime is 181081616987. The reversal of 181081616977 is 779616180181.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 175602064401 + 5479552576 = 419049^2 + 74024^2 .

It is a cyclic number.

It is not a de Polignac number, because 181081616977 - 2³⁵ = 146721878609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181081616987) 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, 523357102 + ... + 523357447.

It is an arithmetic number, because the mean of its divisors is an integer number (45532082925).

Almost surely, 2^181081616977 is an apocalyptic number.

It is an amenable number.

181081616977 is a deficient number, since it is larger than the sum of its proper divisors (1046714723).

181081616977 is a wasteful number, since it uses less digits than its factorization.

181081616977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1046714722.

The product of its (nonzero) digits is 1016064, while the sum is 55.

The spelling of 181081616977 in words is "one hundred eighty-one billion, eighty-one million, six hundred sixteen thousand, nine hundred seventy-seven".