191661197401 has 16 divisors (see below), whose sum is σ = 200139896320. Its totient is φ = 183330915840.

The previous prime is 191661197333. The next prime is 191661197503. The reversal of 191661197401 is 104791166191.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191661197401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191661197201) 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, 2326015 + ... + 2407003.

It is an arithmetic number, because the mean of its divisors is an integer number (12508743520).

Almost surely, 2^191661197401 is an apocalyptic number.

It is an amenable number.

191661197401 is a deficient number, since it is larger than the sum of its proper divisors (8478698919).

191661197401 is an equidigital number, since it uses as much as digits as its factorization.

191661197401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81904.

The product of its (nonzero) digits is 81648, while the sum is 46.

The spelling of 191661197401 in words is "one hundred ninety-one billion, six hundred sixty-one million, one hundred ninety-seven thousand, four hundred one".