20616885578 has 4 divisors (see below), whose sum is σ = 30925328370. Its totient is φ = 10308442788.

The previous prime is 20616885559. The next prime is 20616885623. The reversal of 20616885578 is 87558861602.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87558861602 = 2 ⋅43779430801.

It can be written as a sum of positive squares in only one way, i.e., 19441561489 + 1175324089 = 139433^2 + 34283^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5154221393 + ... + 5154221396.

Almost surely, 2^20616885578 is an apocalyptic number.

20616885578 is a deficient number, since it is larger than the sum of its proper divisors (10308442792).

20616885578 is a wasteful number, since it uses less digits than its factorization.

20616885578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10308442791.

The product of its (nonzero) digits is 6451200, while the sum is 56.

The spelling of 20616885578 in words is "twenty billion, six hundred sixteen million, eight hundred eighty-five thousand, five hundred seventy-eight".