21550212 has 36 divisors (see below), whose sum is σ = 56494256. Its totient is φ = 7183080.

The previous prime is 21550201. The next prime is 21550229. The reversal of 21550212 is 21205512.

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10114 + ... + 12057.

Almost surely, 2^21550212 is an apocalyptic number.

It is an amenable number.

21550212 is an abundant number, since it is smaller than the sum of its proper divisors (34944044).

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

21550212 is a wasteful number, since it uses less digits than its factorization.

21550212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22190 (or 22176 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21550212 is about 4642.2205893301. The cubic root of 21550212 is about 278.2811881548.

Adding to 21550212 its reverse (21205512), we get a palindrome (42755724).

The spelling of 21550212 in words is "twenty-one million, five hundred fifty thousand, two hundred twelve".