195975821 has 4 divisors (see below), whose sum is σ = 199673532. Its totient is φ = 192278112.

The previous prime is 195975817. The next prime is 195975827. The reversal of 195975821 is 128579591.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 53436100 + 142539721 = 7310^2 + 11939^2 .

It is a cyclic number.

It is not a de Polignac number, because 195975821 - 2² = 195975817 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 (195975827) 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, 1848776 + ... + 1848881.

It is an arithmetic number, because the mean of its divisors is an integer number (49918383).

Almost surely, 2^195975821 is an apocalyptic number.

It is an amenable number.

195975821 is a deficient number, since it is larger than the sum of its proper divisors (3697711).

195975821 is an equidigital number, since it uses as much as digits as its factorization.

195975821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3697710.

The product of its digits is 226800, while the sum is 47.

The square root of 195975821 is about 13999.1364376521. The cubic root of 195975821 is about 580.8546862125.

The spelling of 195975821 in words is "one hundred ninety-five million, nine hundred seventy-five thousand, eight hundred twenty-one".