1001156556 has 24 divisors (see below), whose sum is σ = 2338132720. Its totient is φ = 333418752.

The previous prime is 1001156551. The next prime is 1001156579. The reversal of 1001156556 is 6556511001.

It is a super-2 number, since 2×1001156556² = 2004628899243562272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1001156551) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 23401 + ... + 50496.

Almost surely, 2^1001156556 is an apocalyptic number.

It is an amenable number.

1001156556 is an abundant number, since it is smaller than the sum of its proper divisors (1336976164).

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

1001156556 is a wasteful number, since it uses less digits than its factorization.

1001156556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75033 (or 75031 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 30.

The square root of 1001156556 is about 31641.0580733325. The cubic root of 1001156556 is about 1000.3853701374.

Adding to 1001156556 its reverse (6556511001), we get a palindrome (7557667557).

The spelling of 1001156556 in words is "one billion, one million, one hundred fifty-six thousand, five hundred fifty-six".