21250265 has 24 divisors (see below), whose sum is σ = 27496008. Its totient is φ = 15759360.

The previous prime is 21250253. The next prime is 21250279. The reversal of 21250265 is 56205212.

It can be written as a sum of positive squares in 4 ways, for example, as 283024 + 20967241 = 532^2 + 4579^2 .

It is not a de Polignac number, because 21250265 - 2¹⁴ = 21233881 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21250265.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 110009 + ... + 110201.

It is an arithmetic number, because the mean of its divisors is an integer number (1145667).

Almost surely, 2^21250265 is an apocalyptic number.

It is an amenable number.

21250265 is a deficient number, since it is larger than the sum of its proper divisors (6245743).

21250265 is a wasteful number, since it uses less digits than its factorization.

21250265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297 (or 278 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 21250265 is about 4609.8009718425. The cubic root of 21250265 is about 276.9840642129.

Adding to 21250265 its reverse (56205212), we get a palindrome (77455477).

The spelling of 21250265 in words is "twenty-one million, two hundred fifty thousand, two hundred sixty-five".