21172000015 has 8 divisors (see below), whose sum is σ = 25413516288. Its totient is φ = 16932855840.

The previous prime is 21171999917. The next prime is 21172000021. The reversal of 21172000015 is 51000027112.

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

It is not a de Polignac number, because 21172000015 - 2⁹ = 21171999503 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21171999956 and 21172000001.

It is a congruent number.

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, 573327 + ... + 609136.

It is an arithmetic number, because the mean of its divisors is an integer number (3176689536).

Almost surely, 2^21172000015 is an apocalyptic number.

21172000015 is a deficient number, since it is larger than the sum of its proper divisors (4241516273).

21172000015 is a wasteful number, since it uses less digits than its factorization.

21172000015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1186049.

The product of its (nonzero) digits is 140, while the sum is 19.

Adding to 21172000015 its reverse (51000027112), we get a palindrome (72172027127).

The spelling of 21172000015 in words is "twenty-one billion, one hundred seventy-two million, fifteen", and thus it is an aban number.