161783772578 has 8 divisors (see below), whose sum is σ = 249234460572. Its totient is φ = 78705619056.

The previous prime is 161783772547. The next prime is 161783772659. The reversal of 161783772578 is 875277387161.

It can be written as a sum of positive squares in 2 ways, for example, as 157519290769 + 4264481809 = 396887^2 + 65303^2 .

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 161783772578.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1093133525 + ... + 1093133672.

Almost surely, 2^161783772578 is an apocalyptic number.

161783772578 is a deficient number, since it is larger than the sum of its proper divisors (87450687994).

161783772578 is a wasteful number, since it uses less digits than its factorization.

161783772578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2186267236.

The product of its digits is 27659520, while the sum is 62.

The spelling of 161783772578 in words is "one hundred sixty-one billion, seven hundred eighty-three million, seven hundred seventy-two thousand, five hundred seventy-eight".