195720821 has 8 divisors (see below), whose sum is σ = 200692800. Its totient is φ = 190768032.

The previous prime is 195720817. The next prime is 195720853. The reversal of 195720821 is 128027591.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 195720821 - 2² = 195720817 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 (195720871) 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 7 ways as a sum of consecutive naturals, for example, 17105 + ... + 26153.

It is an arithmetic number, because the mean of its divisors is an integer number (25086600).

Almost surely, 2^195720821 is an apocalyptic number.

It is an amenable number.

195720821 is a deficient number, since it is larger than the sum of its proper divisors (4971979).

195720821 is an equidigital number, since it uses as much as digits as its factorization.

195720821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9595.

The product of its (nonzero) digits is 10080, while the sum is 35.

The square root of 195720821 is about 13990.0257683823. The cubic root of 195720821 is about 580.6026445176.

The spelling of 195720821 in words is "one hundred ninety-five million, seven hundred twenty thousand, eight hundred twenty-one".