1231011220 has 24 divisors (see below), whose sum is σ = 2588993064. Its totient is φ = 491667456.

The previous prime is 1231011217. The next prime is 1231011233. The reversal of 1231011220 is 221101321.

It can be written as a sum of positive squares in 4 ways, for example, as 5171076 + 1225840144 = 2274^2 + 35012^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1231011220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32269 + ... + 59188.

It is an arithmetic number, because the mean of its divisors is an integer number (107874711).

Almost surely, 2^1231011220 is an apocalyptic number.

1231011220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231011220 is an abundant number, since it is smaller than the sum of its proper divisors (1357981844).

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

1231011220 is a wasteful number, since it uses less digits than its factorization.

1231011220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92139 (or 92137 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1231011220 is about 35085.7694799473. The cubic root of 1231011220 is about 1071.7348106286.

Adding to 1231011220 its reverse (221101321), we get a palindrome (1452112541).

The spelling of 1231011220 in words is "one billion, two hundred thirty-one million, eleven thousand, two hundred twenty".