1231305500 has 48 divisors (see below), whose sum is σ = 2693256384. Its totient is φ = 491774400.

The previous prime is 1231305497. The next prime is 1231305511. The reversal of 1231305500 is 55031321.

It is a super-2 number, since 2×1231305500² = 3032226468660500000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

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, 425057 + ... + 427943.

It is an arithmetic number, because the mean of its divisors is an integer number (56109508).

Almost surely, 2^1231305500 is an apocalyptic number.

1231305500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1231305500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1346628192).

1231305500 is an abundant number, since it is smaller than the sum of its proper divisors (1461950884).

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

1231305500 is a wasteful number, since it uses less digits than its factorization.

1231305500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3759 (or 3747 counting only the distinct ones).

The product of its (nonzero) digits is 450, while the sum is 20.

The square root of 1231305500 is about 35089.9629523885. The cubic root of 1231305500 is about 1071.8202051905.

Adding to 1231305500 its reverse (55031321), we get a palindrome (1286336821).

The spelling of 1231305500 in words is "one billion, two hundred thirty-one million, three hundred five thousand, five hundred".