21851671705 has 8 divisors (see below), whose sum is σ = 26223005952. Its totient is φ = 17480670768.

The previous prime is 21851671691. The next prime is 21851671711. The reversal of 21851671705 is 50717615812.

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 21851671705 - 2²¹ = 21849574553 is a prime.

It is a Duffinian 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, 95992 + ... + 230038.

It is an arithmetic number, because the mean of its divisors is an integer number (3277875744).

Almost surely, 2^21851671705 is an apocalyptic number.

It is an amenable number.

21851671705 is a deficient number, since it is larger than the sum of its proper divisors (4371334247).

21851671705 is a wasteful number, since it uses less digits than its factorization.

21851671705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166655.

The product of its (nonzero) digits is 117600, while the sum is 43.

The spelling of 21851671705 in words is "twenty-one billion, eight hundred fifty-one million, six hundred seventy-one thousand, seven hundred five".