21921750 has 48 divisors (see below), whose sum is σ = 59282496. Its totient is φ = 5845200.

The previous prime is 21921749. The next prime is 21921751. The reversal of 21921750 is 5712912.

It is an interprime number because it is at equal distance from previous prime (21921749) and next prime (21921751).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21921751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2622 + ... + 7121.

It is an arithmetic number, because the mean of its divisors is an integer number (1235052).

Almost surely, 2^21921750 is an apocalyptic number.

21921750 is an abundant number, since it is smaller than the sum of its proper divisors (37360746).

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

21921750 is a wasteful number, since it uses less digits than its factorization.

21921750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9766 (or 9753 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 21921750 is about 4682.0668512955. The cubic root of 21921750 is about 279.8713269322.

The spelling of 21921750 in words is "twenty-one million, nine hundred twenty-one thousand, seven hundred fifty".