21203840212 has 12 divisors (see below), whose sum is σ = 37474114356. Its totient is φ = 10496950400.

The previous prime is 21203840173. The next prime is 21203840213. The reversal of 21203840212 is 21204830212.

It can be written as a sum of positive squares in 2 ways, for example, as 10675848976 + 10527991236 = 103324^2 + 102606^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203840213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26241973 + ... + 26242780.

It is an arithmetic number, because the mean of its divisors is an integer number (3122842863).

Almost surely, 2^21203840212 is an apocalyptic number.

It is an amenable number.

21203840212 is a deficient number, since it is larger than the sum of its proper divisors (16270274144).

21203840212 is a wasteful number, since it uses less digits than its factorization.

21203840212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52484858 (or 52484856 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The spelling of 21203840212 in words is "twenty-one billion, two hundred three million, eight hundred forty thousand, two hundred twelve".