21602225 has 12 divisors (see below), whose sum is σ = 26844636. Its totient is φ = 17244480.

The previous prime is 21602197. The next prime is 21602237. The reversal of 21602225 is 52220612.

It can be written as a sum of positive squares in 6 ways, for example, as 10764961 + 10837264 = 3281^2 + 3292^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21602225 is a prime.

It is a super-2 number, since 2×21602225² = 933312249901250, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21602197 and 21602206.

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, 20819 + ... + 21831.

It is an arithmetic number, because the mean of its divisors is an integer number (2237053).

Almost surely, 2^21602225 is an apocalyptic number.

21602225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21602225 is a deficient number, since it is larger than the sum of its proper divisors (5242411).

21602225 is a wasteful number, since it uses less digits than its factorization.

21602225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1876 (or 1871 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21602225 is about 4647.8193811722. The cubic root of 21602225 is about 278.5048922210.

Adding to 21602225 its reverse (52220612), we get a palindrome (73822837).

The spelling of 21602225 in words is "twenty-one million, six hundred two thousand, two hundred twenty-five".