21131222 has 16 divisors (see below), whose sum is σ = 36362400. Its totient is φ = 9021888.

The previous prime is 21131191. The next prime is 21131251. The reversal of 21131222 is 22213112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21131197 and 21131206.

It is a congruent number.

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, 1154 + ... + 6602.

It is an arithmetic number, because the mean of its divisors is an integer number (2272650).

Almost surely, 2^21131222 is an apocalyptic number.

21131222 is a deficient number, since it is larger than the sum of its proper divisors (15231178).

21131222 is a wasteful number, since it uses less digits than its factorization.

21131222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5735.

The product of its digits is 48, while the sum is 14.

The square root of 21131222 is about 4596.8708922483. The cubic root of 21131222 is about 276.4658780884.

Adding to 21131222 its reverse (22213112), we get a palindrome (43344334).

The spelling of 21131222 in words is "twenty-one million, one hundred thirty-one thousand, two hundred twenty-two".