21425042 has 8 divisors (see below), whose sum is σ = 32921532. Its totient is φ = 10451200.

The previous prime is 21425023. The next prime is 21425057. The reversal of 21425042 is 24052412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16883881 + 4541161 = 4109^2 + 2131^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 130559 + ... + 130722.

Almost surely, 2^21425042 is an apocalyptic number.

21425042 is a deficient number, since it is larger than the sum of its proper divisors (11496490).

21425042 is a wasteful number, since it uses less digits than its factorization.

21425042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261324.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21425042 is about 4628.7192613076. The cubic root of 21425042 is about 277.7413618514.

Adding to 21425042 its reverse (24052412), we get a palindrome (45477454).

The spelling of 21425042 in words is "twenty-one million, four hundred twenty-five thousand, forty-two".