21738225 has 12 divisors (see below), whose sum is σ = 35940656. Its totient is φ = 11593680.

The previous prime is 21738221. The next prime is 21738239. The reversal of 21738225 is 52283712.

It is not a de Polignac number, because 21738225 - 2² = 21738221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21738192 and 21738201.

It is not an unprimeable number, because it can be changed into a prime (21738221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 144847 + ... + 144996.

Almost surely, 2^21738225 is an apocalyptic number.

21738225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21738225 is a deficient number, since it is larger than the sum of its proper divisors (14202431).

21738225 is a wasteful number, since it uses less digits than its factorization.

21738225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289856 (or 289851 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 21738225 is about 4662.4269431274. The cubic root of 21738225 is about 279.0881262187.

The spelling of 21738225 in words is "twenty-one million, seven hundred thirty-eight thousand, two hundred twenty-five".