61881995313121 has 27 divisors (see below), whose sum is σ = 64336814962329. Its totient is φ = 59518399818528.

The previous prime is 61881995313049. The next prime is 61881995313143. The reversal of 61881995313121 is 12131359918816.

The square root of 61881995313121 is 7866511.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 12209608350625 + 49672386962496 = 3494225^2 + 7047864^2 .

It is not a de Polignac number, because 61881995313121 - 2¹⁵ = 61881995280353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61881995311121) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 111098734575 + ... + 111098735131.

Almost surely, 2^{61881995313121} is an apocalyptic number.

61881995313121 is the 7866511-st square number.

61881995313121 is the 3933256-th centered octagonal number.

It is an amenable number.

61881995313121 is a deficient number, since it is larger than the sum of its proper divisors (2454819649208).

61881995313121 is an frugal number, since it uses more digits than its factorization.

61881995313121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2146 (or 1073 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 58.

The spelling of 61881995313121 in words is "sixty-one trillion, eight hundred eighty-one billion, nine hundred ninety-five million, three hundred thirteen thousand, one hundred twenty-one".