18220212 has 36 divisors (see below), whose sum is σ = 46817316. Its totient is φ = 5973120.

The previous prime is 18220193. The next prime is 18220247. The reversal of 18220212 is 21202281.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9960336 + 8259876 = 3156^2 + 2874^2 .

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

It is a super-2 number, since 2×18220212² = 663952250649888, which contains 22 as substring.

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

It is a congruent number.

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, 1953 + ... + 6344.

It is an arithmetic number, because the mean of its divisors is an integer number (1300481).

Almost surely, 2^18220212 is an apocalyptic number.

18220212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18220212 is an abundant number, since it is smaller than the sum of its proper divisors (28597104).

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

18220212 is a wasteful number, since it uses less digits than its factorization.

18220212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8368 (or 8363 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 18220212 is about 4268.5140271528. The cubic root of 18220212 is about 263.1385488291.

Adding to 18220212 its reverse (21202281), we get a palindrome (39422493).

The spelling of 18220212 in words is "eighteen million, two hundred twenty thousand, two hundred twelve".