21025426 has 4 divisors (see below), whose sum is σ = 31538142. Its totient is φ = 10512712.

The previous prime is 21025423. The next prime is 21025439. The reversal of 21025426 is 62452012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18481401 + 2544025 = 4299^2 + 1595^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21025397 and 21025406.

It is not an unprimeable number, because it can be changed into a prime (21025423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5256355 + ... + 5256358.

Almost surely, 2^21025426 is an apocalyptic number.

21025426 is a deficient number, since it is larger than the sum of its proper divisors (10512716).

21025426 is a wasteful number, since it uses less digits than its factorization.

21025426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10512715.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21025426 is about 4585.3490597772. The cubic root of 21025426 is about 276.0037194066.

Adding to 21025426 its reverse (62452012), we get a palindrome (83477438).

The spelling of 21025426 in words is "twenty-one million, twenty-five thousand, four hundred twenty-six".