61561660515066 has 40 divisors (see below), whose sum is σ = 138741083394804. Its totient is φ = 20401937579520.

The previous prime is 61561660515037. The next prime is 61561660515071. The reversal of 61561660515066 is 66051506616516.

61561660515066 is a `hidden beast` number, since 6 + 1 + 5 + 6 + 1 + 6 + 60 + 515 + 0 + 66 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 58940612843841 + 2621047671225 = 7677279^2 + 1618965^2 .

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1098267495 + ... + 1098323546.

Almost surely, 2^{61561660515066} is an apocalyptic number.

61561660515066 is an abundant number, since it is smaller than the sum of its proper divisors (77179422879738).

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

61561660515066 is a wasteful number, since it uses less digits than its factorization.

61561660515066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2196591228 (or 2196591219 counting only the distinct ones).

The product of its (nonzero) digits is 5832000, while the sum is 54.

The spelling of 61561660515066 in words is "sixty-one trillion, five hundred sixty-one billion, six hundred sixty million, five hundred fifteen thousand, sixty-six".