1561055566 has 32 divisors (see below), whose sum is σ = 2902640832. Its totient is φ = 614307840.

The previous prime is 1561055543. The next prime is 1561055597. The reversal of 1561055566 is 6655501651.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70231 + ... + 89746.

It is an arithmetic number, because the mean of its divisors is an integer number (90707526).

Almost surely, 2^1561055566 is an apocalyptic number.

1561055566 is a deficient number, since it is larger than the sum of its proper divisors (1341585266).

1561055566 is a wasteful number, since it uses less digits than its factorization.

1561055566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160044.

The product of its (nonzero) digits is 135000, while the sum is 40.

The square root of 1561055566 is about 39510.1957221171. The cubic root of 1561055566 is about 1160.0395264970.

The spelling of 1561055566 in words is "one billion, five hundred sixty-one million, fifty-five thousand, five hundred sixty-six".