21654425 has 12 divisors (see below), whose sum is σ = 28917420. Its totient is φ = 15990720.

The previous prime is 21654421. The next prime is 21654427. The reversal of 21654425 is 52445612.

It can be written as a sum of positive squares in 6 ways, for example, as 4481689 + 17172736 = 2117^2 + 4144^2 .

It is not a de Polignac number, because 21654425 - 2² = 21654421 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21654421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32990 + ... + 33639.

It is an arithmetic number, because the mean of its divisors is an integer number (2409785).

Almost surely, 2^21654425 is an apocalyptic number.

21654425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21654425 is a deficient number, since it is larger than the sum of its proper divisors (7262995).

21654425 is a wasteful number, since it uses less digits than its factorization.

21654425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66652 (or 66647 counting only the distinct ones).

The product of its digits is 9600, while the sum is 29.

The square root of 21654425 is about 4653.4315295274. The cubic root of 21654425 is about 278.7290398284.

The spelling of 21654425 in words is "twenty-one million, six hundred fifty-four thousand, four hundred twenty-five".