21209150 has 24 divisors (see below), whose sum is σ = 40812120. Its totient is φ = 8190560.

The previous prime is 21209141. The next prime is 21209161. The reversal of 21209150 is 5190212.

It is a Curzon number.

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 11 ways as a sum of consecutive naturals, for example, 5864 + ... + 8763.

It is an arithmetic number, because the mean of its divisors is an integer number (1700505).

Almost surely, 2^21209150 is an apocalyptic number.

21209150 is a deficient number, since it is larger than the sum of its proper divisors (19602970).

21209150 is a wasteful number, since it uses less digits than its factorization.

21209150 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14668 (or 14663 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 21209150 is about 4605.3392926037. The cubic root of 21209150 is about 276.8053126799.

Adding to 21209150 its reverse (5190212), we get a palindrome (26399362).

The spelling of 21209150 in words is "twenty-one million, two hundred nine thousand, one hundred fifty".