991423211 has 16 divisors (see below), whose sum is σ = 1093843200. Its totient is φ = 894392928.

The previous prime is 991423201. The next prime is 991423229. The reversal of 991423211 is 112324199.

It is a de Polignac number, because none of the positive numbers 2^k-991423211 is a prime.

It is not an unprimeable number, because it can be changed into a prime (991423201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95120 + ... + 105026.

It is an arithmetic number, because the mean of its divisors is an integer number (68365200).

Almost surely, 2^991423211 is an apocalyptic number.

991423211 is a deficient number, since it is larger than the sum of its proper divisors (102419989).

991423211 is a wasteful number, since it uses less digits than its factorization.

991423211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10178.

The product of its digits is 3888, while the sum is 32.

The square root of 991423211 is about 31486.8736301336. The cubic root of 991423211 is about 997.1328576847.

The spelling of 991423211 in words is "nine hundred ninety-one million, four hundred twenty-three thousand, two hundred eleven".