1211235220 has 24 divisors (see below), whose sum is σ = 2739255624. Its totient is φ = 447225216.

The previous prime is 1211235211. The next prime is 1211235229. The reversal of 1211235220 is 225321121.

It is an interprime number because it is at equal distance from previous prime (1211235211) and next prime (1211235229).

It can be written as a sum of positive squares in 4 ways, for example, as 21123216 + 1190112004 = 4596^2 + 34498^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211235229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2329039 + ... + 2329558.

It is an arithmetic number, because the mean of its divisors is an integer number (114135651).

Almost surely, 2^1211235220 is an apocalyptic number.

1211235220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211235220 is an abundant number, since it is smaller than the sum of its proper divisors (1528020404).

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

1211235220 is a wasteful number, since it uses less digits than its factorization.

1211235220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4658619 (or 4658617 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 1211235220 is about 34802.8047720295. The cubic root of 1211235220 is about 1065.9647176352.

Adding to 1211235220 its reverse (225321121), we get a palindrome (1436556341).

The spelling of 1211235220 in words is "one billion, two hundred eleven million, two hundred thirty-five thousand, two hundred twenty".