21297779812 has 6 divisors (see below), whose sum is σ = 37271114678. Its totient is φ = 10648889904.

The previous prime is 21297779773. The next prime is 21297779861. The reversal of 21297779812 is 21897779212.

It can be written as a sum of positive squares in only one way, i.e., 20367285796 + 930494016 = 142714^2 + 30504^2 .

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 as a sum of consecutive naturals, namely, 2662222473 + ... + 2662222480.

Almost surely, 2^21297779812 is an apocalyptic number.

It is an amenable number.

21297779812 is a deficient number, since it is larger than the sum of its proper divisors (15973334866).

21297779812 is a wasteful number, since it uses less digits than its factorization.

21297779812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5324444957 (or 5324444955 counting only the distinct ones).

The product of its digits is 1778112, while the sum is 55.

The spelling of 21297779812 in words is "twenty-one billion, two hundred ninety-seven million, seven hundred seventy-nine thousand, eight hundred twelve".