21208180712 has 16 divisors (see below), whose sum is σ = 39770045700. Its totient is φ = 10602835200.

The previous prime is 21208180649. The next prime is 21208180717. The reversal of 21208180712 is 21708180212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 15763806916 + 5444373796 = 125554^2 + 73786^2 .

It is a super-2 number, since 2×21208180712² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21208180717) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 83039 + ... + 222062.

Almost surely, 2^21208180712 is an apocalyptic number.

It is an amenable number.

21208180712 is a deficient number, since it is larger than the sum of its proper divisors (18561864988).

21208180712 is a wasteful number, since it uses less digits than its factorization.

21208180712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313796 (or 313792 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 32.

The spelling of 21208180712 in words is "twenty-one billion, two hundred eight million, one hundred eighty thousand, seven hundred twelve".