21036634565 has 8 divisors (see below), whose sum is σ = 26058283008. Its totient is φ = 16286426640.

The previous prime is 21036634561. The next prime is 21036634589. The reversal of 21036634565 is 56543663012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21036634565 - 2² = 21036634561 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036634561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67859957 + ... + 67860266.

It is an arithmetic number, because the mean of its divisors is an integer number (3257285376).

Almost surely, 2^21036634565 is an apocalyptic number.

It is an amenable number.

21036634565 is a deficient number, since it is larger than the sum of its proper divisors (5021648443).

21036634565 is a wasteful number, since it uses less digits than its factorization.

21036634565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135720259.

The product of its (nonzero) digits is 388800, while the sum is 41.

The spelling of 21036634565 in words is "twenty-one billion, thirty-six million, six hundred thirty-four thousand, five hundred sixty-five".