20665286787 has 16 divisors (see below), whose sum is σ = 29013152000. Its totient is φ = 13047601824.

The previous prime is 20665286779. The next prime is 20665286827. The reversal of 20665286787 is 78768256602.

It is a happy number.

It is not a de Polignac number, because 20665286787 - 2³ = 20665286779 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is not an unprimeable number, because it can be changed into a prime (20665216787) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 127914 + ... + 240192.

It is an arithmetic number, because the mean of its divisors is an integer number (1813322000).

Almost surely, 2^20665286787 is an apocalyptic number.

20665286787 is a deficient number, since it is larger than the sum of its proper divisors (8347865213).

20665286787 is a wasteful number, since it uses less digits than its factorization.

20665286787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115530.

The product of its (nonzero) digits is 13547520, while the sum is 57.

The spelling of 20665286787 in words is "twenty billion, six hundred sixty-five million, two hundred eighty-six thousand, seven hundred eighty-seven".