1001661556600 has 48 divisors (see below), whose sum is σ = 2352872062800. Its totient is φ = 396534051840.

The previous prime is 1001661556591. The next prime is 1001661556661. The reversal of 1001661556600 is 66551661001.

It is a self number, because there is not a number n which added to its sum of digits gives 1001661556600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25796620 + ... + 25835419.

It is an arithmetic number, because the mean of its divisors is an integer number (49018167975).

Almost surely, 2^{1001661556600} is an apocalyptic number.

1001661556600 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1001661556600 is an abundant number, since it is smaller than the sum of its proper divisors (1351210506200).

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

1001661556600 is a wasteful number, since it uses less digits than its factorization.

1001661556600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51632152 (or 51632143 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 37.

The spelling of 1001661556600 in words is "one trillion, one billion, six hundred sixty-one million, five hundred fifty-six thousand, six hundred".