20505012986 has 4 divisors (see below), whose sum is σ = 30757519482. Its totient is φ = 10252506492.

The previous prime is 20505012959. The next prime is 20505012989. The reversal of 20505012986 is 68921050502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68921050502 = 2 ⋅34460525251.

It can be written as a sum of positive squares in only one way, i.e., 19078515625 + 1426497361 = 138125^2 + 37769^2 .

It is not an unprimeable number, because it can be changed into a prime (20505012989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5126253245 + ... + 5126253248.

Almost surely, 2^20505012986 is an apocalyptic number.

20505012986 is a deficient number, since it is larger than the sum of its proper divisors (10252506496).

20505012986 is a wasteful number, since it uses less digits than its factorization.

20505012986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10252506495.

The product of its (nonzero) digits is 43200, while the sum is 38.

The spelling of 20505012986 in words is "twenty billion, five hundred five million, twelve thousand, nine hundred eighty-six".