991011013321 has 4 divisors (see below), whose sum is σ = 1132584015232. Its totient is φ = 849438011412.

The previous prime is 991011013319. The next prime is 991011013357. The reversal of 991011013321 is 123310110199.

991011013321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 991011013321 - 2¹ = 991011013319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991011013301) 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, 70786500945 + ... + 70786500958.

It is an arithmetic number, because the mean of its divisors is an integer number (283146003808).

Almost surely, 2^991011013321 is an apocalyptic number.

It is an amenable number.

991011013321 is a deficient number, since it is larger than the sum of its proper divisors (141573001911).

991011013321 is a wasteful number, since it uses less digits than its factorization.

991011013321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141573001910.

The product of its (nonzero) digits is 1458, while the sum is 31.

The spelling of 991011013321 in words is "nine hundred ninety-one billion, eleven million, thirteen thousand, three hundred twenty-one".