684211212 has 54 divisors (see below), whose sum is σ = 1795731028. Its totient is φ = 227798568.

The previous prime is 684211201. The next prime is 684211217. The reversal of 684211212 is 212112486.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is a tau number, because it is divible by the number of its divisors (54).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (684211217) by changing a digit.

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 17 ways as a sum of consecutive naturals, for example, 815089 + ... + 815927.

Almost surely, 2^684211212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 684211212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (897865514).

684211212 is an abundant number, since it is smaller than the sum of its proper divisors (1111519816).

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

684211212 is an frugal number, since it uses more digits than its factorization.

684211212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1697 (or 844 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 684211212 is about 26157.4312959052. The cubic root of 684211212 is about 881.1774922688.

Multiplying 684211212 by its sum of digits (27), we get a square (18473702724 = 135918²).

684211212 divided by its sum of digits (27) gives a square (25341156 = 5034²).

Adding to 684211212 its reverse (212112486), we get a palindrome (896323698).

The spelling of 684211212 in words is "six hundred eighty-four million, two hundred eleven thousand, two hundred twelve".