195904021 has 4 divisors (see below), whose sum is σ = 196041600. Its totient is φ = 195766444.

The previous prime is 195903991. The next prime is 195904031. The reversal of 195904021 is 120409591.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 195904021 - 2⁷ = 195903893 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 (195904031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66631 + ... + 69508.

It is an arithmetic number, because the mean of its divisors is an integer number (49010400).

Almost surely, 2^195904021 is an apocalyptic number.

It is an amenable number.

195904021 is a deficient number, since it is larger than the sum of its proper divisors (137579).

195904021 is a wasteful number, since it uses less digits than its factorization.

195904021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137578.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 195904021 is about 13996.5717588272. The cubic root of 195904021 is about 580.7837413029.

The spelling of 195904021 in words is "one hundred ninety-five million, nine hundred four thousand, twenty-one".