191021008 has 40 divisors (see below), whose sum is σ = 383475456. Its totient is φ = 92083200.

The previous prime is 191020987. The next prime is 191021011. The reversal of 191021008 is 800120191.

It is a self number, because there is not a number n which added to its sum of digits gives 191021008.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 174543 + ... + 175633.

Almost surely, 2^191021008 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 191021008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191737728).

191021008 is an abundant number, since it is smaller than the sum of its proper divisors (192454448).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

191021008 is a wasteful number, since it uses less digits than its factorization.

191021008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1483 (or 1477 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 191021008 is about 13821.0349829526. The cubic root of 191021008 is about 575.9176354709.

Adding to 191021008 its reverse (800120191), we get a palindrome (991141199).

The spelling of 191021008 in words is "one hundred ninety-one million, twenty-one thousand, eight".