15561066561081 has 16 divisors (see below), whose sum is σ = 21292961389440. Its totient is φ = 10104910312320.

The previous prime is 15561066561071. The next prime is 15561066561091. The reversal of 15561066561081 is 18016566016551.

It is an interprime number because it is at equal distance from previous prime (15561066561071) and next prime (15561066561091).

It is not a de Polignac number, because 15561066561081 - 2⁵ = 15561066561049 is a prime.

It is a super-2 number, since 2×15561066561081² (a number of 27 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (15561066561041) 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, 412763436 + ... + 412801133.

It is an arithmetic number, because the mean of its divisors is an integer number (1330810086840).

Almost surely, 2^{15561066561081} is an apocalyptic number.

It is an amenable number.

15561066561081 is a deficient number, since it is larger than the sum of its proper divisors (5731894828359).

15561066561081 is a wasteful number, since it uses less digits than its factorization.

15561066561081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825564736.

The product of its (nonzero) digits is 1296000, while the sum is 51.

The spelling of 15561066561081 in words is "fifteen trillion, five hundred sixty-one billion, sixty-six million, five hundred sixty-one thousand, eighty-one".