15661695916378 has 8 divisors (see below), whose sum is σ = 23700442493268. Its totient is φ = 7761548418624.

The previous prime is 15661695916369. The next prime is 15661695916397. The reversal of 15661695916378 is 87361959616651.

It can be written as a sum of positive squares in 2 ways, for example, as 11110842223849 + 4550853692529 = 3333293^2 + 2133273^2 .

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 15661695916378.

It is an unprimeable number.

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, 34649769501 + ... + 34649769952.

Almost surely, 2^{15661695916378} is an apocalyptic number.

15661695916378 is a deficient number, since it is larger than the sum of its proper divisors (8038746576890).

15661695916378 is a wasteful number, since it uses less digits than its factorization.

15661695916378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69299539568.

The product of its digits is 440899200, while the sum is 73.

The spelling of 15661695916378 in words is "fifteen trillion, six hundred sixty-one billion, six hundred ninety-five million, nine hundred sixteen thousand, three hundred seventy-eight".