21220125 has 32 divisors (see below), whose sum is σ = 35852544. Its totient is φ = 11144000.

The previous prime is 21220109. The next prime is 21220153. The reversal of 21220125 is 52102212.

It is not a de Polignac number, because 21220125 - 2⁴ = 21220109 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 26227 + ... + 27023.

It is an arithmetic number, because the mean of its divisors is an integer number (1120392).

Almost surely, 2^21220125 is an apocalyptic number.

21220125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21220125 is a deficient number, since it is larger than the sum of its proper divisors (14632419).

21220125 is an equidigital number, since it uses as much as digits as its factorization.

21220125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 886 (or 876 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21220125 is about 4606.5306902266. The cubic root of 21220125 is about 276.8530501651.

Adding to 21220125 its reverse (52102212), we get a palindrome (73322337).

It can be divided in two parts, 212201 and 25, that added together give a triangular number (212226 = T₆₅₁).

The spelling of 21220125 in words is "twenty-one million, two hundred twenty thousand, one hundred twenty-five".