191061596881 has 4 divisors (see below), whose sum is σ = 191062499764. Its totient is φ = 191060694000.

The previous prime is 191061596863. The next prime is 191061596903. The reversal of 191061596881 is 188695160191.

191061596881 = T₃₅₆₈₉₄ + T₃₅₆₈₉₅ + T₃₅₆₈₉₆.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 188695160191 = 6469 ⋅29169139.

It can be written as a sum of positive squares in 2 ways, for example, as 129827619856 + 61233977025 = 360316^2 + 247455^2 .

It is a 3-Lehmer number, since φ(191061596881) divides (191061596881-1)³.

It is a cyclic number.

It is not a de Polignac number, because 191061596881 - 2⁵ = 191061596849 is a prime.

It is a super-2 number, since 2×191061596881² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191061596081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56431 + ... + 620731.

It is an arithmetic number, because the mean of its divisors is an integer number (47765624941).

Almost surely, 2^191061596881 is an apocalyptic number.

191061596881 is the 356896-th centered triangular number.

It is an amenable number.

191061596881 is a deficient number, since it is larger than the sum of its proper divisors (902883).

191061596881 is an equidigital number, since it uses as much as digits as its factorization.

191061596881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902882.

The product of its (nonzero) digits is 933120, while the sum is 55.

The spelling of 191061596881 in words is "one hundred ninety-one billion, sixty-one million, five hundred ninety-six thousand, eight hundred eighty-one".