20787289565 has 16 divisors (see below), whose sum is σ = 28511035392. Its totient is φ = 14252765184.

The previous prime is 20787289561. The next prime is 20787289591. The reversal of 20787289565 is 56598278702.

It is not a de Polignac number, because 20787289565 - 2² = 20787289561 is a prime.

It is a super-2 number, since 2×20787289565² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20787289561) 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, 452957 + ... + 496733.

It is an arithmetic number, because the mean of its divisors is an integer number (1781939712).

Almost surely, 2^20787289565 is an apocalyptic number.

It is an amenable number.

20787289565 is a deficient number, since it is larger than the sum of its proper divisors (7723745827).

20787289565 is a wasteful number, since it uses less digits than its factorization.

20787289565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57356.

The product of its (nonzero) digits is 16934400, while the sum is 59.

The spelling of 20787289565 in words is "twenty billion, seven hundred eighty-seven million, two hundred eighty-nine thousand, five hundred sixty-five".