21215122 has 8 divisors (see below), whose sum is σ = 32598972. Its totient is φ = 10348800.

The previous prime is 21215111. The next prime is 21215137. The reversal of 21215122 is 22151212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20620681 + 594441 = 4541^2 + 771^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21215096 and 21215105.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129279 + ... + 129442.

Almost surely, 2^21215122 is an apocalyptic number.

21215122 is a deficient number, since it is larger than the sum of its proper divisors (11383850).

21215122 is a wasteful number, since it uses less digits than its factorization.

21215122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258764.

The product of its digits is 80, while the sum is 16.

The square root of 21215122 is about 4605.9876248205. The cubic root of 21215122 is about 276.8312908732.

Adding to 21215122 its reverse (22151212), we get a palindrome (43366334).

The spelling of 21215122 in words is "twenty-one million, two hundred fifteen thousand, one hundred twenty-two".