21025045 has 4 divisors (see below), whose sum is σ = 25230060. Its totient is φ = 16820032.

The previous prime is 21025031. The next prime is 21025051. The reversal of 21025045 is 54052012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13593969 + 7431076 = 3687^2 + 2726^2 .

It is a cyclic number.

It is not a de Polignac number, because 21025045 - 2¹¹ = 21022997 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2102500 + ... + 2102509.

It is an arithmetic number, because the mean of its divisors is an integer number (6307515).

Almost surely, 2^21025045 is an apocalyptic number.

It is an amenable number.

21025045 is a deficient number, since it is larger than the sum of its proper divisors (4205015).

21025045 is an equidigital number, since it uses as much as digits as its factorization.

21025045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4205014.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 21025045 is about 4585.3075142241. The cubic root of 21025045 is about 276.0020522497.

Adding to 21025045 its reverse (54052012), we get a palindrome (75077057).

The spelling of 21025045 in words is "twenty-one million, twenty-five thousand, forty-five".