21222131 has 8 divisors (see below), whose sum is σ = 24440064. Its totient is φ = 18050760.

The previous prime is 21222043. The next prime is 21222143. The reversal of 21222131 is 13122212.

It is a happy number.

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

It is not a de Polignac number, because 21222131 - 2¹⁸ = 20959987 is a prime.

It is a super-2 number, since 2×21222131² = 900757688362322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21222181) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10655 + ... + 12488.

It is an arithmetic number, because the mean of its divisors is an integer number (3055008).

Almost surely, 2^21222131 is an apocalyptic number.

21222131 is a deficient number, since it is larger than the sum of its proper divisors (3217933).

21222131 is a wasteful number, since it uses less digits than its factorization.

21222131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23281.

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

The square root of 21222131 is about 4606.7484194386. The cubic root of 21222131 is about 276.8617737976.

Adding to 21222131 its reverse (13122212), we get a palindrome (34344343).

The spelling of 21222131 in words is "twenty-one million, two hundred twenty-two thousand, one hundred thirty-one".