1231131220 has 48 divisors (see below), whose sum is σ = 2968862400. Its totient is φ = 424120320.

The previous prime is 1231131217. The next prime is 1231131233. The reversal of 1231131220 is 221311321.

It is a junction number, because it is equal to n+sod(n) for n = 1231131194 and 1231131203.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 143085 + ... + 151444.

It is an arithmetic number, because the mean of its divisors is an integer number (61851300).

Almost surely, 2^1231131220 is an apocalyptic number.

1231131220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231131220 is an abundant number, since it is smaller than the sum of its proper divisors (1737731180).

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

1231131220 is a wasteful number, since it uses less digits than its factorization.

1231131220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294568 (or 294566 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1231131220 is about 35087.4795333036. The cubic root of 1231131220 is about 1071.7696340313.

Adding to 1231131220 its reverse (221311321), we get a palindrome (1452442541).

The spelling of 1231131220 in words is "one billion, two hundred thirty-one million, one hundred thirty-one thousand, two hundred twenty".