21001212203212 has 24 divisors (see below), whose sum is σ = 38062730442240. Its totient is φ = 10132439803920.

The previous prime is 21001212203207. The next prime is 21001212203267. The reversal of 21001212203212 is 21230221210012.

It is a self number, because there is not a number n which added to its sum of digits gives 21001212203212.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 786666762 + ... + 786693457.

It is an arithmetic number, because the mean of its divisors is an integer number (1585947101760).

Almost surely, 2^{21001212203212} is an apocalyptic number.

It is an amenable number.

21001212203212 is a deficient number, since it is larger than the sum of its proper divisors (17061518239028).

21001212203212 is a wasteful number, since it uses less digits than its factorization.

21001212203212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1573360341 (or 1573360339 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21001212203212 its reverse (21230221210012), we get a palindrome (42231433413224).

The spelling of 21001212203212 in words is "twenty-one trillion, one billion, two hundred twelve million, two hundred three thousand, two hundred twelve".