21203640212 has 6 divisors (see below), whose sum is σ = 37106370378. Its totient is φ = 10601820104.

The previous prime is 21203640187. The next prime is 21203640221. The reversal of 21203640212 is 21204630212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 14591673616 + 6611966596 = 120796^2 + 81314^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2650455023 + ... + 2650455030.

It is an arithmetic number, because the mean of its divisors is an integer number (6184395063).

Almost surely, 2^21203640212 is an apocalyptic number.

It is an amenable number.

21203640212 is a deficient number, since it is larger than the sum of its proper divisors (15902730166).

21203640212 is a wasteful number, since it uses less digits than its factorization.

21203640212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5300910057 (or 5300910055 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The spelling of 21203640212 in words is "twenty-one billion, two hundred three million, six hundred forty thousand, two hundred twelve".