20688716836 has 6 divisors (see below), whose sum is σ = 36205254470. Its totient is φ = 10344358416.

The previous prime is 20688716777. The next prime is 20688716837. The reversal of 20688716836 is 63861788602.

It can be written as a sum of positive squares in only one way, i.e., 16579137600 + 4109579236 = 128760^2 + 64106^2 .

It is not an unprimeable number, because it can be changed into a prime (20688716837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2586089601 + ... + 2586089608.

Almost surely, 2^20688716836 is an apocalyptic number.

It is an amenable number.

20688716836 is a deficient number, since it is larger than the sum of its proper divisors (15516537634).

20688716836 is a wasteful number, since it uses less digits than its factorization.

20688716836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5172179213 (or 5172179211 counting only the distinct ones).

The product of its (nonzero) digits is 4644864, while the sum is 55.

The spelling of 20688716836 in words is "twenty billion, six hundred eighty-eight million, seven hundred sixteen thousand, eight hundred thirty-six".