21224425 has 12 divisors (see below), whose sum is σ = 27704080. Its totient is φ = 16085520.

The previous prime is 21224389. The next prime is 21224431. The reversal of 21224425 is 52442212.

It is not a de Polignac number, because 21224425 - 2⁷ = 21224297 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21224396 and 21224405.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21867 + ... + 22816.

Almost surely, 2^21224425 is an apocalyptic number.

21224425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21224425 is a deficient number, since it is larger than the sum of its proper divisors (6479655).

21224425 is a wasteful number, since it uses less digits than its factorization.

21224425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44712 (or 44707 counting only the distinct ones).

The product of its digits is 1280, while the sum is 22.

The square root of 21224425 is about 4606.9973952673. The cubic root of 21224425 is about 276.8717492022.

Adding to 21224425 its reverse (52442212), we get a palindrome (73666637).

The spelling of 21224425 in words is "twenty-one million, two hundred twenty-four thousand, four hundred twenty-five".