21012222 has 32 divisors (see below), whose sum is σ = 52395264. Its totient is φ = 5457600.

The previous prime is 21012193. The next prime is 21012227. The reversal of 21012222 is 22221012.

It is a junction number, because it is equal to n+sod(n) for n = 21012198 and 21012207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22279 + ... + 23202.

It is an arithmetic number, because the mean of its divisors is an integer number (1637352).

Almost surely, 2^21012222 is an apocalyptic number.

21012222 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21012222 is an abundant number, since it is smaller than the sum of its proper divisors (31383042).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21012222 is a wasteful number, since it uses less digits than its factorization.

21012222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45504.

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21012222 is about 4583.9090305110. The cubic root of 21012222 is about 275.9459303870.

Adding to 21012222 its reverse (22221012), we get a palindrome (43233234).

It can be divided in two parts, 21012 and 222, that multiplied together give a palindrome (4664664).

The spelling of 21012222 in words is "twenty-one million, twelve thousand, two hundred twenty-two".