21221202122212 has 6 divisors (see below), whose sum is σ = 37137103713878. Its totient is φ = 10610601061104.

The previous prime is 21221202122149. The next prime is 21221202122257. The reversal of 21221202122212 is 21222120212212.

It can be written as a sum of positive squares in only one way, i.e., 19369381936356 + 1851820185856 = 4401066^2 + 1360816^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2652650265273 + ... + 2652650265280.

Almost surely, 2^{21221202122212} is an apocalyptic number.

It is an amenable number.

21221202122212 is a deficient number, since it is larger than the sum of its proper divisors (15915901591666).

21221202122212 is a wasteful number, since it uses less digits than its factorization.

21221202122212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5305300530557 (or 5305300530555 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21221202122212 its reverse (21222120212212), we get a palindrome (42443322334424).

Subtracting 21221202122212 from its reverse (21222120212212), we obtain a square (918090000 = 30300²).

The spelling of 21221202122212 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred two million, one hundred twenty-two thousand, two hundred twelve".