21250516 has 18 divisors (see below), whose sum is σ = 43260378. Its totient is φ = 9107280.

The previous prime is 21250511. The next prime is 21250517. The reversal of 21250516 is 61505212.

It can be written as a sum of positive squares in only one way, i.e., 18835600 + 2414916 = 4340^2 + 1554^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21250511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54015 + ... + 54406.

Almost surely, 2^21250516 is an apocalyptic number.

It is an amenable number.

21250516 is an abundant number, since it is smaller than the sum of its proper divisors (22009862).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21250516 is a wasteful number, since it uses less digits than its factorization.

21250516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108439 (or 108430 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 21250516 is about 4609.8281963648. The cubic root of 21250516 is about 276.9851547519.

Adding to 21250516 its reverse (61505212), we get a palindrome (82755728).

It can be divided in two parts, 212505 and 16, that added together give a square (212521 = 461²).

The spelling of 21250516 in words is "twenty-one million, two hundred fifty thousand, five hundred sixteen".