1231101220 has 24 divisors (see below), whose sum is σ = 2697718464. Its totient is φ = 471029856.

The previous prime is 1231101211. The next prime is 1231101229. The reversal of 1231101220 is 221011321.

It is an interprime number because it is at equal distance from previous prime (1231101211) and next prime (1231101229).

It is a super-2 number, since 2×1231101220² = 3031220427770976800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1231101220.

It is not an unprimeable number, because it can be changed into a prime (1231101229) 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, 1337694 + ... + 1338613.

It is an arithmetic number, because the mean of its divisors is an integer number (112404936).

Almost surely, 2^1231101220 is an apocalyptic number.

1231101220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231101220 is an abundant number, since it is smaller than the sum of its proper divisors (1466617244).

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

1231101220 is a wasteful number, since it uses less digits than its factorization.

1231101220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2676339 (or 2676337 counting only the distinct ones).

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

The square root of 1231101220 is about 35087.0520277780. The cubic root of 1231101220 is about 1071.7609283928.

Adding to 1231101220 its reverse (221011321), we get a palindrome (1452112541).

It can be divided in two parts, 1231101 and 220, that added together give a palindrome (1231321).

The spelling of 1231101220 in words is "one billion, two hundred thirty-one million, one hundred one thousand, two hundred twenty".