1231978440 has 768 divisors, whose sum is σ = 5295144960. Its totient is φ = 223027200.

The previous prime is 1231978403. The next prime is 1231978453. The reversal of 1231978440 is 448791321.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 39741225 + ... + 39741255.

It is an arithmetic number, because the mean of its divisors is an integer number (6894720).

Almost surely, 2^1231978440 is an apocalyptic number.

1231978440 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 1231978440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2647572480).

1231978440 is an abundant number, since it is smaller than the sum of its proper divisors (4063166520).

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

1231978440 is a wasteful number, since it uses less digits than its factorization.

1231978440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114 (or 99 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 1231978440 is about 35099.5504244713. The cubic root of 1231978440 is about 1072.0154286968.

The spelling of 1231978440 in words is "one billion, two hundred thirty-one million, nine hundred seventy-eight thousand, four hundred forty".