161137656781138 has 8 divisors (see below), whose sum is σ = 241706647288332. Its totient is φ = 80568774351696.

The previous prime is 161137656781133. The next prime is 161137656781207. The reversal of 161137656781138 is 831187656731161.

It can be written as a sum of positive squares in 2 ways, for example, as 141541868796769 + 19595787984369 = 11897137^2 + 4426713^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 161137656781138.

It is not an unprimeable number, because it can be changed into a prime (161137656781133) 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, 23183145 + ... + 29321212.

Almost surely, 2^{161137656781138} is an apocalyptic number.

161137656781138 is a deficient number, since it is larger than the sum of its proper divisors (80568990507194).

161137656781138 is a wasteful number, since it uses less digits than its factorization.

161137656781138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54038876.

The product of its digits is 30481920, while the sum is 64.

The spelling of 161137656781138 in words is "one hundred sixty-one trillion, one hundred thirty-seven billion, six hundred fifty-six million, seven hundred eighty-one thousand, one hundred thirty-eight".