21645703871 has 8 divisors (see below), whose sum is σ = 24059033424. Its totient is φ = 19306630720.

The previous prime is 21645703861. The next prime is 21645703889. The reversal of 21645703871 is 17830754612.

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 21645703871 - 2¹⁴ = 21645687487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21645703861) 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, 18563486 + ... + 18564651.

It is an arithmetic number, because the mean of its divisors is an integer number (3007379178).

Almost surely, 2^21645703871 is an apocalyptic number.

21645703871 is a deficient number, since it is larger than the sum of its proper divisors (2413329553).

21645703871 is a wasteful number, since it uses less digits than its factorization.

21645703871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37128201.

The product of its (nonzero) digits is 282240, while the sum is 44.

The spelling of 21645703871 in words is "twenty-one billion, six hundred forty-five million, seven hundred three thousand, eight hundred seventy-one".