21250660 has 24 divisors (see below), whose sum is σ = 44868096. Its totient is φ = 8454240.

The previous prime is 21250637. The next prime is 21250687. The reversal of 21250660 is 6605212.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1039 + ... + 6601.

It is an arithmetic number, because the mean of its divisors is an integer number (1869504).

Almost surely, 2^21250660 is an apocalyptic number.

21250660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21250660 is an abundant number, since it is smaller than the sum of its proper divisors (23617436).

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

21250660 is a wasteful number, since it uses less digits than its factorization.

21250660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5763 (or 5761 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21250660 is about 4609.8438151417. The cubic root of 21250660 is about 276.9857803958.

Adding to 21250660 its reverse (6605212), we get a palindrome (27855872).

The spelling of 21250660 in words is "twenty-one million, two hundred fifty thousand, six hundred sixty".