21750890 has 16 divisors (see below), whose sum is σ = 44744832. Its totient is φ = 7457424.

The previous prime is 21750887. The next prime is 21750901. The reversal of 21750890 is 9805712.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 155294 + ... + 155433.

It is an arithmetic number, because the mean of its divisors is an integer number (2796552).

Almost surely, 2^21750890 is an apocalyptic number.

21750890 is an abundant number, since it is smaller than the sum of its proper divisors (22993942).

21750890 is a wasteful number, since it uses less digits than its factorization.

21750890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310741.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 21750890 is about 4663.7849435839. The cubic root of 21750890 is about 279.1423159375.

The spelling of 21750890 in words is "twenty-one million, seven hundred fifty thousand, eight hundred ninety".