1211217812 has 48 divisors (see below), whose sum is σ = 2531450880. Its totient is φ = 495799392.

The previous prime is 1211217797. The next prime is 1211217817. The reversal of 1211217812 is 2187121121.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211217817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 840989 + ... + 842427.

It is an arithmetic number, because the mean of its divisors is an integer number (52738560).

Almost surely, 2^1211217812 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 1211217812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1265725440).

1211217812 is an abundant number, since it is smaller than the sum of its proper divisors (1320233068).

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

1211217812 is a wasteful number, since it uses less digits than its factorization.

1211217812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2780 (or 2778 counting only the distinct ones).

The product of its digits is 448, while the sum is 26.

The square root of 1211217812 is about 34802.5546763452. The cubic root of 1211217812 is about 1065.9596108917.

Adding to 1211217812 its reverse (2187121121), we get a palindrome (3398338933).

The spelling of 1211217812 in words is "one billion, two hundred eleven million, two hundred seventeen thousand, eight hundred twelve".