991000213 has 4 divisors (see below), whose sum is σ = 1132571680. Its totient is φ = 849428748.

The previous prime is 991000207. The next prime is 991000229. The reversal of 991000213 is 312000199.

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 de Polignac number, because none of the positive numbers 2^k-991000213 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 (991000243) 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, 70785723 + ... + 70785736.

It is an arithmetic number, because the mean of its divisors is an integer number (283142920).

Almost surely, 2^991000213 is an apocalyptic number.

It is an amenable number.

991000213 is a deficient number, since it is larger than the sum of its proper divisors (141571467).

991000213 is a wasteful number, since it uses less digits than its factorization.

991000213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141571466.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 991000213 is about 31480.1558604782. The cubic root of 991000213 is about 996.9910261574.

The spelling of 991000213 in words is "nine hundred ninety-one million, two hundred thirteen", and thus it is an aban number.