211221012 has 72 divisors (see below), whose sum is σ = 520649248. Its totient is φ = 66597120.

The previous prime is 211220993. The next prime is 211221013. The reversal of 211221012 is 210122112.

211221012 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×211221012² = 89228631820608288, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221013) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 746223 + ... + 746505.

Almost surely, 2^211221012 is an apocalyptic number.

It is an amenable number.

211221012 is an abundant number, since it is smaller than the sum of its proper divisors (309428236).

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

211221012 is a wasteful number, since it uses less digits than its factorization.

211221012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 211221012 is about 14533.4446020205. Note that the first 3 decimals coincide. The cubic root of 211221012 is about 595.5419697579.

Adding to 211221012 its reverse (210122112), we get a palindrome (421343124).

It can be divided in two parts, 2112 and 21012, that multiplied together give a palindrome (44377344).

The spelling of 211221012 in words is "two hundred eleven million, two hundred twenty-one thousand, twelve".