991570313 has 4 divisors (see below), whose sum is σ = 993204480. Its totient is φ = 989936148.

The previous prime is 991570303. The next prime is 991570331. The reversal of 991570313 is 313075199.

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 991570313 - 2⁶ = 991570249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991570303) 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, 816173 + ... + 817386.

It is an arithmetic number, because the mean of its divisors is an integer number (248301120).

Almost surely, 2^991570313 is an apocalyptic number.

It is an amenable number.

991570313 is a deficient number, since it is larger than the sum of its proper divisors (1634167).

991570313 is a wasteful number, since it uses less digits than its factorization.

991570313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1634166.

The product of its (nonzero) digits is 25515, while the sum is 38.

The square root of 991570313 is about 31489.2094692769. The cubic root of 991570313 is about 997.1821716346.

The spelling of 991570313 in words is "nine hundred ninety-one million, five hundred seventy thousand, three hundred thirteen".