21435225 has 24 divisors (see below), whose sum is σ = 40503360. Its totient is φ = 9798720.

The previous prime is 21435163. The next prime is 21435233. The reversal of 21435225 is 52253412.

It is not a de Polignac number, because 21435225 - 2¹² = 21431129 is a prime.

It is a super-4 number, since 4×21435225⁴ (a number of 30 digits) contains 4444 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21435195 and 21435204.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19890 + ... + 20939.

It is an arithmetic number, because the mean of its divisors is an integer number (1687640).

Almost surely, 2^21435225 is an apocalyptic number.

21435225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21435225 is a deficient number, since it is larger than the sum of its proper divisors (19068135).

21435225 is a wasteful number, since it uses less digits than its factorization.

21435225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40849 (or 40844 counting only the distinct ones).

The product of its digits is 2400, while the sum is 24.

The square root of 21435225 is about 4629.8191109373. The cubic root of 21435225 is about 277.7853569784.

Adding to 21435225 its reverse (52253412), we get a palindrome (73688637).

The spelling of 21435225 in words is "twenty-one million, four hundred thirty-five thousand, two hundred twenty-five".