21268648779 has 16 divisors (see below), whose sum is σ = 34315803648. Its totient is φ = 11438600832.

The previous prime is 21268648717. The next prime is 21268648783. The reversal of 21268648779 is 97784686212.

It is a happy number.

It is not a de Polignac number, because 21268648779 - 2⁷ = 21268648651 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21268648789) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29787667 + ... + 29788380.

It is an arithmetic number, because the mean of its divisors is an integer number (2144737728).

Almost surely, 2^21268648779 is an apocalyptic number.

21268648779 is a deficient number, since it is larger than the sum of its proper divisors (13047154869).

21268648779 is a wasteful number, since it uses less digits than its factorization.

21268648779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59576074.

The product of its digits is 16257024, while the sum is 60.

The spelling of 21268648779 in words is "twenty-one billion, two hundred sixty-eight million, six hundred forty-eight thousand, seven hundred seventy-nine".