1231531420 has 48 divisors (see below), whose sum is σ = 3051030528. Its totient is φ = 408617280.

The previous prime is 1231531409. The next prime is 1231531453. The reversal of 1231531420 is 241351321.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1231531391 and 1231531400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 137542 + ... + 146221.

It is an arithmetic number, because the mean of its divisors is an integer number (63563136).

Almost surely, 2^1231531420 is an apocalyptic number.

1231531420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231531420 is an abundant number, since it is smaller than the sum of its proper divisors (1819499108).

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

1231531420 is a wasteful number, since it uses less digits than its factorization.

1231531420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283810 (or 283808 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 1231531420 is about 35093.1819588934. The cubic root of 1231531420 is about 1071.8857537248.

Adding to 1231531420 its reverse (241351321), we get a palindrome (1472882741).

The spelling of 1231531420 in words is "one billion, two hundred thirty-one million, five hundred thirty-one thousand, four hundred twenty".