1211000001220 has 12 divisors (see below), whose sum is σ = 2543100002604. Its totient is φ = 484400000480.

The previous prime is 1211000001209. The next prime is 1211000001223. The reversal of 1211000001220 is 221000001121.

It can be written as a sum of positive squares in 2 ways, for example, as 134353037764 + 1076646963456 = 366542^2 + 1037616^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 1211000001197 and 1211000001206.

It is not an unprimeable number, because it can be changed into a prime (1211000001223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30275000011 + ... + 30275000050.

It is an arithmetic number, because the mean of its divisors is an integer number (211925000217).

Almost surely, 2^{1211000001220} is an apocalyptic number.

1211000001220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211000001220 is an abundant number, since it is smaller than the sum of its proper divisors (1332100001384).

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

1211000001220 is a wasteful number, since it uses less digits than its factorization.

1211000001220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60550000070 (or 60550000068 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 1211000001220 its reverse (221000001121), we get a palindrome (1432000002341).

Subtracting from 1211000001220 its reverse (221000001121), we obtain a palindrome (990000000099).

The spelling of 1211000001220 in words is "one trillion, two hundred eleven billion, one thousand, two hundred twenty".