21683750 has 80 divisors (see below), whose sum is σ = 47234880. Its totient is φ = 7380000.

The previous prime is 21683749. The next prime is 21683759. The reversal of 21683750 is 5738612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21683759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 261209 + ... + 261291.

It is an arithmetic number, because the mean of its divisors is an integer number (590436).

Almost surely, 2^21683750 is an apocalyptic number.

21683750 is an abundant number, since it is smaller than the sum of its proper divisors (25551130).

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

21683750 is a wasteful number, since it uses less digits than its factorization.

21683750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21683750 is about 4656.5813640481. The cubic root of 21683750 is about 278.8548038415.

The spelling of 21683750 in words is "twenty-one million, six hundred eighty-three thousand, seven hundred fifty".