191640945 has 32 divisors (see below), whose sum is σ = 328626432. Its totient is φ = 95116032.

The previous prime is 191640919. The next prime is 191640947. The reversal of 191640945 is 549046191.

It is not a de Polignac number, because 191640945 - 2¹¹ = 191638897 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (191640947) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5259 + ... + 20271.

It is an arithmetic number, because the mean of its divisors is an integer number (10269576).

Almost surely, 2^191640945 is an apocalyptic number.

191640945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

191640945 is a deficient number, since it is larger than the sum of its proper divisors (136985487).

191640945 is a wasteful number, since it uses less digits than its factorization.

191640945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15081.

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 191640945 is about 13843.4441162595. Note that the first 3 decimals coincide. The cubic root of 191640945 is about 576.5399878035.

The spelling of 191640945 in words is "one hundred ninety-one million, six hundred forty thousand, nine hundred forty-five".