21440425 has 12 divisors (see below), whose sum is σ = 27503820. Its totient is φ = 16560320.

The previous prime is 21440411. The next prime is 21440431. The reversal of 21440425 is 52404412.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 2334784 + 19105641 = 1528^2 + 4371^2 .

It is not a de Polignac number, because 21440425 - 2¹³ = 21432233 is a prime.

It is a plaindrome in base 11.

It is a junction number, because it is equal to n+sod(n) for n = 21440396 and 21440405.

It is an unprimeable number.

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, 14062 + ... + 15511.

It is an arithmetic number, because the mean of its divisors is an integer number (2291985).

Almost surely, 2^21440425 is an apocalyptic number.

21440425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21440425 is a deficient number, since it is larger than the sum of its proper divisors (6063395).

21440425 is a wasteful number, since it uses less digits than its factorization.

21440425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29612 (or 29607 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 21440425 is about 4630.3806538988. The cubic root of 21440425 is about 277.8078179364.

Adding to 21440425 its reverse (52404412), we get a palindrome (73844837).

The spelling of 21440425 in words is "twenty-one million, four hundred forty thousand, four hundred twenty-five".