1231555240 has 32 divisors (see below), whose sum is σ = 2891479680. Its totient is φ = 471203392.

The previous prime is 1231555231. The next prime is 1231555271. The reversal of 1231555240 is 425551321.

It is a junction number, because it is equal to n+sod(n) for n = 1231555199 and 1231555208.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 668404 + ... + 670243.

It is an arithmetic number, because the mean of its divisors is an integer number (90358740).

Almost surely, 2^1231555240 is an apocalyptic number.

1231555240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231555240 is an abundant number, since it is smaller than the sum of its proper divisors (1659924440).

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

1231555240 is a wasteful number, since it uses less digits than its factorization.

1231555240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1338681 (or 1338677 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 1231555240 is about 35093.5213394153. The cubic root of 1231555240 is about 1071.8926644036.

The spelling of 1231555240 in words is "one billion, two hundred thirty-one million, five hundred fifty-five thousand, two hundred forty".