991309141 has 4 divisors (see below), whose sum is σ = 991387692. Its totient is φ = 991230592.

The previous prime is 991309139. The next prime is 991309157. The reversal of 991309141 is 141903199.

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.

It can be written as a sum of positive squares in 2 ways, for example, as 628254225 + 363054916 = 25065^2 + 19054^2 .

It is a cyclic number.

It is not a de Polignac number, because 991309141 - 2¹ = 991309139 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 991309141.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991309541) 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, 15580 + ... + 47173.

It is an arithmetic number, because the mean of its divisors is an integer number (247846923).

Almost surely, 2^991309141 is an apocalyptic number.

It is an amenable number.

991309141 is a deficient number, since it is larger than the sum of its proper divisors (78551).

991309141 is a wasteful number, since it uses less digits than its factorization.

991309141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78550.

The product of its (nonzero) digits is 8748, while the sum is 37.

The square root of 991309141 is about 31485.0621882822. The cubic root of 991309141 is about 997.0946139067.

The spelling of 991309141 in words is "nine hundred ninety-one million, three hundred nine thousand, one hundred forty-one".