21724278871 has 8 divisors (see below), whose sum is σ = 21906542000. Its totient is φ = 21542571648.

The previous prime is 21724278857. The next prime is 21724278907. The reversal of 21724278871 is 17887242712.

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 21724278871 - 2³¹ = 19576795223 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 (21724278071) 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, 60306 + ... + 216991.

It is an arithmetic number, because the mean of its divisors is an integer number (2738317750).

Almost surely, 2^21724278871 is an apocalyptic number.

21724278871 is a deficient number, since it is larger than the sum of its proper divisors (182263129).

21724278871 is a wasteful number, since it uses less digits than its factorization.

21724278871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277953.

The product of its digits is 702464, while the sum is 49.

The spelling of 21724278871 in words is "twenty-one billion, seven hundred twenty-four million, two hundred seventy-eight thousand, eight hundred seventy-one".