1231000020 has 144 divisors (see below), whose sum is σ = 3911281920. Its totient is φ = 312795648.

The previous prime is 1231000009. The next prime is 1231000037. The reversal of 1231000020 is 200001321.

It is a happy number.

It is a super-2 number, since 2×1231000020² = 3030722098480000800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 1230999966 and 1231000011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1692897 + ... + 1693623.

It is an arithmetic number, because the mean of its divisors is an integer number (27161680).

Almost surely, 2^1231000020 is an apocalyptic number.

1231000020 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 1231000020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1955640960).

1231000020 is an abundant number, since it is smaller than the sum of its proper divisors (2680281900).

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

1231000020 is a wasteful number, since it uses less digits than its factorization.

1231000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1174 (or 1169 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 1231000020 is about 35085.6098707148. The cubic root of 1231000020 is about 1071.7315603288.

Adding to 1231000020 its reverse (200001321), we get a palindrome (1431001341).

The spelling of 1231000020 in words is "one billion, two hundred thirty-one million, twenty", and thus it is an aban number.