21012212 has 12 divisors (see below), whose sum is σ = 39600036. Its totient is φ = 9697920.

The previous prime is 21012193. The next prime is 21012227. The reversal of 21012212 is 21221012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 10797796 + 10214416 = 3286^2 + 3196^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21012193 and 21012202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201989 + ... + 202092.

It is an arithmetic number, because the mean of its divisors is an integer number (3300003).

Almost surely, 2^21012212 is an apocalyptic number.

It is an amenable number.

21012212 is a deficient number, since it is larger than the sum of its proper divisors (18587824).

21012212 is a wasteful number, since it uses less digits than its factorization.

21012212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404098 (or 404096 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21012212 is about 4583.9079397388. The cubic root of 21012212 is about 275.9458866115.

Adding to 21012212 its reverse (21221012), we get a palindrome (42233224).

It can be divided in two parts, 21012 and 212, that multiplied together give a palindrome (4454544).

The spelling of 21012212 in words is "twenty-one million, twelve thousand, two hundred twelve".