61200891818181 has 48 divisors (see below), whose sum is σ = 94082906936304. Its totient is φ = 38203030075392.

The previous prime is 61200891818177. The next prime is 61200891818191. The reversal of 61200891818181 is 18181819800216.

61200891818181 is a `hidden beast` number, since 6 + 1 + 200 + 89 + 181 + 8 + 181 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 1341811789956 + 59859080028225 = 1158366^2 + 7736865^2 .

It is not a de Polignac number, because 61200891818181 - 2² = 61200891818177 is a prime.

It is a super-2 number, since 2×61200891818181² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61200891818191) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 503082895 + ... + 503204531.

It is an arithmetic number, because the mean of its divisors is an integer number (1960060561173).

Almost surely, 2^{61200891818181} is an apocalyptic number.

It is an amenable number.

61200891818181 is a deficient number, since it is larger than the sum of its proper divisors (32882015118123).

61200891818181 is a wasteful number, since it uses less digits than its factorization.

61200891818181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138550 (or 138547 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 54.

The spelling of 61200891818181 in words is "sixty-one trillion, two hundred billion, eight hundred ninety-one million, eight hundred eighteen thousand, one hundred eighty-one".