21651671610717 has 8 divisors (see below), whose sum is σ = 28869183224160. Its totient is φ = 14434303868880.

The previous prime is 21651671610713. The next prime is 21651671610749. The reversal of 21651671610717 is 71701617615612.

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

It is not a de Polignac number, because 21651671610717 - 2² = 21651671610713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21651671610717.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21651671610713) 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, 35616259 + ... + 36219072.

It is an arithmetic number, because the mean of its divisors is an integer number (3608647903020).

Almost surely, 2^{21651671610717} is an apocalyptic number.

It is an amenable number.

21651671610717 is a deficient number, since it is larger than the sum of its proper divisors (7217511613443).

21651671610717 is a wasteful number, since it uses less digits than its factorization.

21651671610717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71935803.

The product of its (nonzero) digits is 740880, while the sum is 51.

The spelling of 21651671610717 in words is "twenty-one trillion, six hundred fifty-one billion, six hundred seventy-one million, six hundred ten thousand, seven hundred seventeen".