21436516687 has 8 divisors (see below), whose sum is σ = 21848831136. Its totient is φ = 21024493152.

The previous prime is 21436516613. The next prime is 21436516697. The reversal of 21436516687 is 78661563412.

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

It is a cyclic number.

It is not a de Polignac number, because 21436516687 - 2¹¹ = 21436514639 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21436516687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21436516697) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79078 + ... + 221644.

It is an arithmetic number, because the mean of its divisors is an integer number (2731103892).

Almost surely, 2^21436516687 is an apocalyptic number.

21436516687 is a deficient number, since it is larger than the sum of its proper divisors (412314449).

21436516687 is a wasteful number, since it uses less digits than its factorization.

21436516687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145457.

The product of its digits is 1451520, while the sum is 49.

The spelling of 21436516687 in words is "twenty-one billion, four hundred thirty-six million, five hundred sixteen thousand, six hundred eighty-seven".