1231100220 has 96 divisors (see below), whose sum is σ = 4171281408. Its totient is φ = 264840192.

The previous prime is 1231100209. The next prime is 1231100291. The reversal of 1231100220 is 220011321.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1231100196 and 1231100205.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79072 + ... + 93351.

It is an arithmetic number, because the mean of its divisors is an integer number (43450848).

Almost surely, 2^1231100220 is an apocalyptic number.

1231100220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231100220 is an abundant number, since it is smaller than the sum of its proper divisors (2940181188).

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

1231100220 is a wasteful number, since it uses less digits than its factorization.

1231100220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172459 (or 172457 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1231100220 is about 35087.0377775041. The cubic root of 1231100220 is about 1071.7606382024.

Adding to 1231100220 its reverse (220011321), we get a palindrome (1451111541).

The spelling of 1231100220 in words is "one billion, two hundred thirty-one million, one hundred thousand, two hundred twenty".