21250689 has 16 divisors (see below), whose sum is σ = 29804544. Its totient is φ = 13442000.

The previous prime is 21250687. The next prime is 21250693. The reversal of 21250689 is 98605212.

It is a cyclic number.

It is not a de Polignac number, because 21250689 - 2¹ = 21250687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21250687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7864 + ... + 10214.

It is an arithmetic number, because the mean of its divisors is an integer number (1862784).

Almost surely, 2^21250689 is an apocalyptic number.

It is an amenable number.

21250689 is a deficient number, since it is larger than the sum of its proper divisors (8553855).

21250689 is a wasteful number, since it uses less digits than its factorization.

21250689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2508.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 21250689 is about 4609.8469605834. The cubic root of 21250689 is about 276.9859063932.

The spelling of 21250689 in words is "twenty-one million, two hundred fifty thousand, six hundred eighty-nine".