21250925 has 12 divisors (see below), whose sum is σ = 26409396. Its totient is φ = 16963200.

The previous prime is 21250877. The next prime is 21250961. The reversal of 21250925 is 52905212.

It can be written as a sum of positive squares in 6 ways, for example, as 10843849 + 10407076 = 3293^2 + 3226^2 .

It is not a de Polignac number, because 21250925 - 2¹² = 21246829 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21250894 and 21250903.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18467 + ... + 19583.

It is an arithmetic number, because the mean of its divisors is an integer number (2200783).

Almost surely, 2^21250925 is an apocalyptic number.

21250925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21250925 is a deficient number, since it is larger than the sum of its proper divisors (5158471).

21250925 is a wasteful number, since it uses less digits than its factorization.

21250925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1888 (or 1883 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 21250925 is about 4609.8725578914. The cubic root of 21250925 is about 276.9869317472.

The spelling of 21250925 in words is "twenty-one million, two hundred fifty thousand, nine hundred twenty-five".