21250940 has 12 divisors (see below), whose sum is σ = 44627016. Its totient is φ = 8500368.

The previous prime is 21250877. The next prime is 21250961. The reversal of 21250940 is 4905212.

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 3 ways as a sum of consecutive naturals, for example, 531254 + ... + 531293.

It is an arithmetic number, because the mean of its divisors is an integer number (3718918).

Almost surely, 2^21250940 is an apocalyptic number.

21250940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21250940 is an abundant number, since it is smaller than the sum of its proper divisors (23376076).

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

21250940 is a wasteful number, since it uses less digits than its factorization.

21250940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1062556 (or 1062554 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21250940 is about 4609.8741848341. The cubic root of 21250940 is about 276.9869969177.

The spelling of 21250940 in words is "twenty-one million, two hundred fifty thousand, nine hundred forty".