61177666405781 has 4 divisors (see below), whose sum is σ = 61198271887500. Its totient is φ = 61157060924064.

The previous prime is 61177666405759. The next prime is 61177666405811. The reversal of 61177666405781 is 18750466677116.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26922503916100 + 34255162489681 = 5188690^2 + 5852791^2 .

It is a cyclic number.

It is not a de Polignac number, because 61177666405781 - 2¹⁴ = 61177666389397 is a prime.

It is a super-2 number, since 2×61177666405781² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61177666305781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10302736406 + ... + 10302742343.

It is an arithmetic number, because the mean of its divisors is an integer number (15299567971875).

Almost surely, 2^{61177666405781} is an apocalyptic number.

It is an amenable number.

61177666405781 is a deficient number, since it is larger than the sum of its proper divisors (20605481719).

61177666405781 is a wasteful number, since it uses less digits than its factorization.

61177666405781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20605481718.

The product of its (nonzero) digits is 71124480, while the sum is 65.

The spelling of 61177666405781 in words is "sixty-one trillion, one hundred seventy-seven billion, six hundred sixty-six million, four hundred five thousand, seven hundred eighty-one".