191510146561 has 4 divisors (see below), whose sum is σ = 191518015572. Its totient is φ = 191502277552.

The previous prime is 191510146549. The next prime is 191510146571. The reversal of 191510146561 is 165641015191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165641015191 = 1109 ⋅149360699.

It can be written as a sum of positive squares in 2 ways, for example, as 21654888336 + 169855258225 = 147156^2 + 412135^2 .

It is a cyclic number.

It is not a de Polignac number, because 191510146561 - 2⁷ = 191510146433 is a prime.

It is a super-2 number, since 2×191510146561² (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 (191510146501) 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, 3897886 + ... + 3946711.

It is an arithmetic number, because the mean of its divisors is an integer number (47879503893).

Almost surely, 2^191510146561 is an apocalyptic number.

It is an amenable number.

191510146561 is a deficient number, since it is larger than the sum of its proper divisors (7869011).

191510146561 is an equidigital number, since it uses as much as digits as its factorization.

191510146561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7869010.

The product of its (nonzero) digits is 32400, while the sum is 40.

The spelling of 191510146561 in words is "one hundred ninety-one billion, five hundred ten million, one hundred forty-six thousand, five hundred sixty-one".