21550206 has 16 divisors (see below), whose sum is σ = 44265744. Its totient is φ = 6989184.

The previous prime is 21550201. The next prime is 21550229. The reversal of 21550206 is 60205512.

It is a super-2 number, since 2×21550206² = 928822757284872, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550201) 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 7 ways as a sum of consecutive naturals, for example, 48315 + ... + 48758.

It is an arithmetic number, because the mean of its divisors is an integer number (2766609).

Almost surely, 2^21550206 is an apocalyptic number.

21550206 is an abundant number, since it is smaller than the sum of its proper divisors (22715538).

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

21550206 is a wasteful number, since it uses less digits than its factorization.

21550206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97115.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21550206 is about 4642.2199430876. The cubic root of 21550206 is about 278.2811623285.

Adding to 21550206 its reverse (60205512), we get a palindrome (81755718).

The spelling of 21550206 in words is "twenty-one million, five hundred fifty thousand, two hundred six".