191491215 has 64 divisors (see below), whose sum is σ = 340623360. Its totient is φ = 91428480.

The previous prime is 191491211. The next prime is 191491231. The reversal of 191491215 is 512194191.

It is not a de Polignac number, because 191491215 - 2² = 191491211 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191491211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 858594 + ... + 858816.

It is an arithmetic number, because the mean of its divisors is an integer number (5322240).

Almost surely, 2^191491215 is an apocalyptic number.

191491215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

191491215 is a deficient number, since it is larger than the sum of its proper divisors (149132145).

191491215 is a wasteful number, since it uses less digits than its factorization.

191491215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404.

The product of its digits is 3240, while the sum is 33.

The square root of 191491215 is about 13838.0350845053. The cubic root of 191491215 is about 576.3897975188.

The spelling of 191491215 in words is "one hundred ninety-one million, four hundred ninety-one thousand, two hundred fifteen".