16626561778 has 8 divisors (see below), whose sum is σ = 24972790572. Its totient is φ = 8302298256.

The previous prime is 16626561773. The next prime is 16626561797. The reversal of 16626561778 is 87716562661.

It can be written as a sum of positive squares in 2 ways, for example, as 16609281129 + 17280649 = 128877^2 + 4157^2 .

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

It is not an unprimeable number, because it can be changed into a prime (16626561773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5489425 + ... + 5492452.

Almost surely, 2^16626561778 is an apocalyptic number.

16626561778 is a deficient number, since it is larger than the sum of its proper divisors (8346228794).

16626561778 is a wasteful number, since it uses less digits than its factorization.

16626561778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10982636.

The product of its digits is 5080320, while the sum is 55.

The spelling of 16626561778 in words is "sixteen billion, six hundred twenty-six million, five hundred sixty-one thousand, seven hundred seventy-eight".