1001000055561 has 16 divisors (see below), whose sum is σ = 1459458533568. Its totient is φ = 605225678400.

The previous prime is 1001000055557. The next prime is 1001000055571. The reversal of 1001000055561 is 1655500001001.

It is not a de Polignac number, because 1001000055561 - 2² = 1001000055557 is a prime.

It is a super-2 number, since 2×1001000055561² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1001000055571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36011446 + ... + 36039231.

It is an arithmetic number, because the mean of its divisors is an integer number (91216158348).

Almost surely, 2^{1001000055561} is an apocalyptic number.

1001000055561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1001000055561 is a deficient number, since it is larger than the sum of its proper divisors (458458478007).

1001000055561 is a wasteful number, since it uses less digits than its factorization.

1001000055561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72051112.

The product of its (nonzero) digits is 750, while the sum is 24.

Adding to 1001000055561 its reverse (1655500001001), we get a palindrome (2656500056562).

The spelling of 1001000055561 in words is "one trillion, one billion, fifty-five thousand, five hundred sixty-one".