21434425 has 24 divisors (see below), whose sum is σ = 27585536. Its totient is φ = 16511040.

The previous prime is 21434417. The next prime is 21434429. The reversal of 21434425 is 52443412.

It is a happy number.

It is not a de Polignac number, because 21434425 - 2³ = 21434417 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21434425.

It is not an unprimeable number, because it can be changed into a prime (21434429) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136447 + ... + 136603.

Almost surely, 2^21434425 is an apocalyptic number.

21434425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21434425 is a deficient number, since it is larger than the sum of its proper divisors (6151111).

21434425 is a wasteful number, since it uses less digits than its factorization.

21434425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337 (or 332 counting only the distinct ones).

The product of its digits is 3840, while the sum is 25.

The square root of 21434425 is about 4629.7327136672. The cubic root of 21434425 is about 277.7819011240.

Adding to 21434425 its reverse (52443412), we get a palindrome (73877837).

It can be divided in two parts, 214344 and 25, that added together give a square (214369 = 463²).

The spelling of 21434425 in words is "twenty-one million, four hundred thirty-four thousand, four hundred twenty-five".