21370225 has 12 divisors (see below), whose sum is σ = 27146700. Its totient is φ = 16678400.

The previous prime is 21370199. The next prime is 21370249. The reversal of 21370225 is 52207312.

It can be written as a sum of positive squares in 6 ways, for example, as 613089 + 20757136 = 783^2 + 4556^2 .

It is not a de Polignac number, because 21370225 - 2⁹ = 21369713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21370196 and 21370205.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9400 + ... + 11449.

It is an arithmetic number, because the mean of its divisors is an integer number (2262225).

Almost surely, 2^21370225 is an apocalyptic number.

21370225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21370225 is a deficient number, since it is larger than the sum of its proper divisors (5776475).

21370225 is a wasteful number, since it uses less digits than its factorization.

21370225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20900 (or 20895 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21370225 is about 4622.7940685261. The cubic root of 21370225 is about 277.5042880056.

Adding to 21370225 its reverse (52207312), we get a palindrome (73577537).

The spelling of 21370225 in words is "twenty-one million, three hundred seventy thousand, two hundred twenty-five".