21253122 has 24 divisors (see below), whose sum is σ = 50235120. Its totient is φ = 6440280.

The previous prime is 21253121. The next prime is 21253181. The reversal of 21253122 is 22135212.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21253095 and 21253104.

It is not an unprimeable number, because it can be changed into a prime (21253121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53472 + ... + 53867.

It is an arithmetic number, because the mean of its divisors is an integer number (2093130).

Almost surely, 2^21253122 is an apocalyptic number.

21253122 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21253122 is an abundant number, since it is smaller than the sum of its proper divisors (28981998).

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

21253122 is a wasteful number, since it uses less digits than its factorization.

21253122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107358 (or 107355 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 21253122 is about 4610.1108446544. The cubic root of 21253122 is about 276.9964767328.

Adding to 21253122 its reverse (22135212), we get a palindrome (43388334).

The spelling of 21253122 in words is "twenty-one million, two hundred fifty-three thousand, one hundred twenty-two".