21354612716765 has 8 divisors (see below), whose sum is σ = 25821150033888. Its totient is φ = 16953280324240.

The previous prime is 21354612716761. The next prime is 21354612716803. The reversal of 21354612716765 is 56761721645312.

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

It is not a de Polignac number, because 21354612716765 - 2² = 21354612716761 is a prime.

It is a super-2 number, since 2×21354612716765² (a number of 27 digits) contains 22 as substring.

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 21354612716765.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354612716761) 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, 16301230427 + ... + 16301231736.

It is an arithmetic number, because the mean of its divisors is an integer number (3227643754236).

Almost surely, 2^{21354612716765} is an apocalyptic number.

It is an amenable number.

21354612716765 is a deficient number, since it is larger than the sum of its proper divisors (4466537317123).

21354612716765 is a wasteful number, since it uses less digits than its factorization.

21354612716765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32602462299.

The product of its digits is 12700800, while the sum is 56.

The spelling of 21354612716765 in words is "twenty-one trillion, three hundred fifty-four billion, six hundred twelve million, seven hundred sixteen thousand, seven hundred sixty-five".