18400212 has 36 divisors (see below), whose sum is σ = 47305440. Its totient is φ = 6028752.

The previous prime is 18400177. The next prime is 18400237. The reversal of 18400212 is 21200481.

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

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 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, 2208 + ... + 6455.

It is an arithmetic number, because the mean of its divisors is an integer number (1314040).

Almost surely, 2^18400212 is an apocalyptic number.

18400212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18400212 is an abundant number, since it is smaller than the sum of its proper divisors (28905228).

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

18400212 is a wasteful number, since it uses less digits than its factorization.

18400212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8732 (or 8727 counting only the distinct ones).

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

The square root of 18400212 is about 4289.5468292117. The cubic root of 18400212 is about 264.0022382730.

Adding to 18400212 its reverse (21200481), we get a palindrome (39600693).

The spelling of 18400212 in words is "eighteen million, four hundred thousand, two hundred twelve".