21021200212 has 6 divisors (see below), whose sum is σ = 36787100378. Its totient is φ = 10510600104.

The previous prime is 21021200191. The next prime is 21021200243. The reversal of 21021200212 is 21200212012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 11690799376 + 9330400836 = 108124^2 + 96594^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21021200192 and 21021200201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2627650023 + ... + 2627650030.

Almost surely, 2^21021200212 is an apocalyptic number.

It is an amenable number.

21021200212 is a deficient number, since it is larger than the sum of its proper divisors (15765900166).

21021200212 is a wasteful number, since it uses less digits than its factorization.

21021200212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5255300057 (or 5255300055 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21021200212 its reverse (21200212012), we get a palindrome (42221412224).

The spelling of 21021200212 in words is "twenty-one billion, twenty-one million, two hundred thousand, two hundred twelve".