991240451521141 has 4 divisors (see below), whose sum is σ = 992484166015692. Its totient is φ = 989996737026592.

The previous prime is 991240451521097. The next prime is 991240451521147. The reversal of 991240451521141 is 141125154042199.

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 774736566128100 + 216503885393041 = 27834090^2 + 14714071^2 .

It is a cyclic number.

It is not a de Polignac number, because 991240451521141 - 2²⁵ = 991240417966709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991240451521147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 621857246080 + ... + 621857247673.

It is an arithmetic number, because the mean of its divisors is an integer number (248121041503923).

Almost surely, 2^{991240451521141} is an apocalyptic number.

It is an amenable number.

991240451521141 is a deficient number, since it is larger than the sum of its proper divisors (1243714494551).

991240451521141 is a wasteful number, since it uses less digits than its factorization.

991240451521141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243714494550.

The product of its (nonzero) digits is 518400, while the sum is 49.

The spelling of 991240451521141 in words is "nine hundred ninety-one trillion, two hundred forty billion, four hundred fifty-one million, five hundred twenty-one thousand, one hundred forty-one".