199409390895121 has 27 divisors (see below), whose sum is σ = 220326652376649. Its totient is φ = 180342343269000.

The previous prime is 199409390895097. The next prime is 199409390895157. The reversal of 199409390895121 is 121598093904991.

The square root of 199409390895121 is 14121239.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 199409390895121 - 2⁷ = 199409390894993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199409390845121) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 30911388946 + ... + 30911395396.

Almost surely, 2^{199409390895121} is an apocalyptic number.

199409390895121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

199409390895121 is the 14121239-th square number.

199409390895121 is the 7060620-th centered octagonal number.

It is an amenable number.

199409390895121 is a deficient number, since it is larger than the sum of its proper divisors (20917261481528).

199409390895121 is an frugal number, since it uses more digits than its factorization.

199409390895121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13322 (or 6661 counting only the distinct ones).

The product of its (nonzero) digits is 56687040, while the sum is 70.

The spelling of 199409390895121 in words is "one hundred ninety-nine trillion, four hundred nine billion, three hundred ninety million, eight hundred ninety-five thousand, one hundred twenty-one".