199579787975991 has 4 divisors (see below), whose sum is σ = 266106383967992. Its totient is φ = 133053191983992.

The previous prime is 199579787975987. The next prime is 199579787975993.

199579787975991 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 199579787975991 - 2² = 199579787975987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199579787975993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33263297995996 + ... + 33263297996001.

It is an arithmetic number, because the mean of its divisors is an integer number (66526595991998).

Almost surely, 2^{199579787975991} is an apocalyptic number.

199579787975991 is a deficient number, since it is larger than the sum of its proper divisors (66526595992001).

199579787975991 is an equidigital number, since it uses as much as digits as its factorization.

199579787975991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66526595992000.

The product of its digits is 255197968200, while the sum is 102.

The spelling of 199579787975991 in words is "one hundred ninety-nine trillion, five hundred seventy-nine billion, seven hundred eighty-seven million, nine hundred seventy-five thousand, nine hundred ninety-one".