21879819849 has 8 divisors (see below), whose sum is σ = 29173825600. Its totient is φ = 14586180336.

The previous prime is 21879819823. The next prime is 21879819881. The reversal of 21879819849 is 94891897812.

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

It is not a de Polignac number, because 21879819849 - 2⁸ = 21879819593 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21879819849.

It is not an unprimeable number, because it can be changed into a prime (21879819449) 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, 113364 + ... + 237930.

It is an arithmetic number, because the mean of its divisors is an integer number (3646728200).

Almost surely, 2^21879819849 is an apocalyptic number.

It is an amenable number.

21879819849 is a deficient number, since it is larger than the sum of its proper divisors (7294005751).

21879819849 is a wasteful number, since it uses less digits than its factorization.

21879819849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183119.

The product of its digits is 20901888, while the sum is 66.

The spelling of 21879819849 in words is "twenty-one billion, eight hundred seventy-nine million, eight hundred nineteen thousand, eight hundred forty-nine".