21979388770 has 16 divisors (see below), whose sum is σ = 39791590200. Its totient is φ = 8740935424.

The previous prime is 21979388749. The next prime is 21979388801. The reversal of 21979388770 is 7788397912.

It can be written as a sum of positive squares in 4 ways, for example, as 19396411441 + 2582977329 = 139271^2 + 50823^2 .

It is a super-2 number, since 2×21979388770² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21979388699 and 21979388708.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6350695 + ... + 6354154.

Almost surely, 2^21979388770 is an apocalyptic number.

21979388770 is a deficient number, since it is larger than the sum of its proper divisors (17812201430).

21979388770 is a wasteful number, since it uses less digits than its factorization.

21979388770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12705029.

The product of its (nonzero) digits is 10668672, while the sum is 61.

The spelling of 21979388770 in words is "twenty-one billion, nine hundred seventy-nine million, three hundred eighty-eight thousand, seven hundred seventy".