21948216778 has 8 divisors (see below), whose sum is σ = 33687960768. Its totient is φ = 10718896524.

The previous prime is 21948216751. The next prime is 21948216781. The reversal of 21948216778 is 87761284912.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127605826 + ... + 127605997.

It is an arithmetic number, because the mean of its divisors is an integer number (4210995096).

Almost surely, 2^21948216778 is an apocalyptic number.

21948216778 is a deficient number, since it is larger than the sum of its proper divisors (11739743990).

21948216778 is a wasteful number, since it uses less digits than its factorization.

21948216778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255211868.

The product of its digits is 2709504, while the sum is 55.

The spelling of 21948216778 in words is "twenty-one billion, nine hundred forty-eight million, two hundred sixteen thousand, seven hundred seventy-eight".