21643165315 has 8 divisors (see below), whose sum is σ = 25980368400. Its totient is φ = 17308818912.

The previous prime is 21643165253. The next prime is 21643165343. The reversal of 21643165315 is 51356134612.

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 21643165315 - 2²⁹ = 21106294403 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 697465 + ... + 727834.

It is an arithmetic number, because the mean of its divisors is an integer number (3247546050).

Almost surely, 2^21643165315 is an apocalyptic number.

21643165315 is a deficient number, since it is larger than the sum of its proper divisors (4337203085).

21643165315 is a wasteful number, since it uses less digits than its factorization.

21643165315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1428341.

The product of its digits is 64800, while the sum is 37.

Adding to 21643165315 its reverse (51356134612), we get a palindrome (72999299927).

The spelling of 21643165315 in words is "twenty-one billion, six hundred forty-three million, one hundred sixty-five thousand, three hundred fifteen".