1001556561240 has 192 divisors, whose sum is σ = 3301970780160. Its totient is φ = 263235006720.

The previous prime is 1001556561221. The next prime is 1001556561329. The reversal of 1001556561240 is 421656551001.

1001556561240 is a `hidden beast` number, since 1 + 0 + 0 + 1 + 5 + 56 + 561 + 2 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1001556561195 and 1001556561204.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 138199297 + ... + 138206543.

It is an arithmetic number, because the mean of its divisors is an integer number (17197764480).

Almost surely, 2^{1001556561240} is an apocalyptic number.

1001556561240 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 1001556561240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1650985390080).

1001556561240 is an abundant number, since it is smaller than the sum of its proper divisors (2300414218920).

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

1001556561240 is a wasteful number, since it uses less digits than its factorization.

1001556561240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12742 (or 12735 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The spelling of 1001556561240 in words is "one trillion, one billion, five hundred fifty-six million, five hundred sixty-one thousand, two hundred forty".