21425105 has 8 divisors (see below), whose sum is σ = 27687912. Its totient is φ = 15821568.

The previous prime is 21425099. The next prime is 21425147. The reversal of 21425105 is 50152412.

It can be written as a sum of positive squares in 4 ways, for example, as 117649 + 21307456 = 343^2 + 4616^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21425105 - 2¹⁴ = 21408721 is a prime.

It is a super-2 number, since 2×21425105² = 918070248522050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164744 + ... + 164873.

It is an arithmetic number, because the mean of its divisors is an integer number (3460989).

Almost surely, 2^21425105 is an apocalyptic number.

It is an amenable number.

21425105 is a deficient number, since it is larger than the sum of its proper divisors (6262807).

21425105 is a wasteful number, since it uses less digits than its factorization.

21425105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329635.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21425105 is about 4628.7260666408. The cubic root of 21425105 is about 277.7416340825.

Adding to 21425105 its reverse (50152412), we get a palindrome (71577517).

The spelling of 21425105 in words is "twenty-one million, four hundred twenty-five thousand, one hundred five".