1231531840 has 224 divisors, whose sum is σ = 3691542528. Its totient is φ = 380160000.

The previous prime is 1231531837. The next prime is 1231531841. The reversal of 1231531840 is 481351321.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 1231531799 and 1231531808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231531841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3720475 + ... + 3720805.

Almost surely, 2^1231531840 is an apocalyptic number.

1231531840 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 1231531840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1845771264).

1231531840 is an abundant number, since it is smaller than the sum of its proper divisors (2460010688).

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

1231531840 is a wasteful number, since it uses less digits than its factorization.

1231531840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 517 (or 507 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 1231531840 is about 35093.1879429612. The cubic root of 1231531840 is about 1071.8858755764.

The spelling of 1231531840 in words is "one billion, two hundred thirty-one million, five hundred thirty-one thousand, eight hundred forty".