21779472388 has 6 divisors (see below), whose sum is σ = 38114076686. Its totient is φ = 10889736192.

The previous prime is 21779472359. The next prime is 21779472419. The reversal of 21779472388 is 88327497712.

It can be written as a sum of positive squares in only one way, i.e., 20309670144 + 1469802244 = 142512^2 + 38338^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2722434045 + ... + 2722434052.

Almost surely, 2^21779472388 is an apocalyptic number.

It is an amenable number.

21779472388 is a deficient number, since it is larger than the sum of its proper divisors (16334604298).

21779472388 is a wasteful number, since it uses less digits than its factorization.

21779472388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5444868101 (or 5444868099 counting only the distinct ones).

The product of its digits is 9483264, while the sum is 58.

The spelling of 21779472388 in words is "twenty-one billion, seven hundred seventy-nine million, four hundred seventy-two thousand, three hundred eighty-eight".