1561660105601 has 16 divisors (see below), whose sum is σ = 1723026252240. Its totient is φ = 1408756500480.

The previous prime is 1561660105561. The next prime is 1561660105613. The reversal of 1561660105601 is 1065010661651.

It can be written as a sum of positive squares in 8 ways, for example, as 446693059201 + 1114967046400 = 668351^2 + 1055920^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1561660105601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561660105631) 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, 11493290 + ... + 11628371.

It is an arithmetic number, because the mean of its divisors is an integer number (107689140765).

Almost surely, 2^{1561660105601} is an apocalyptic number.

It is an amenable number.

1561660105601 is a deficient number, since it is larger than the sum of its proper divisors (161366146639).

1561660105601 is a wasteful number, since it uses less digits than its factorization.

1561660105601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23121844.

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 1561660105601 in words is "one trillion, five hundred sixty-one billion, six hundred sixty million, one hundred five thousand, six hundred one".