195121639 has 2 divisors, whose sum is σ = 195121640. Its totient is φ = 195121638.

The previous prime is 195121637. The next prime is 195121643. The reversal of 195121639 is 936121591.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (936121591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 195121639 - 2¹ = 195121637 is a prime.

Together with 195121637, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 195121598 and 195121607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195121637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97560819 + 97560820.

It is an arithmetic number, because the mean of its divisors is an integer number (97560820).

Almost surely, 2^195121639 is an apocalyptic number.

195121639 is a deficient number, since it is larger than the sum of its proper divisors (1).

195121639 is an equidigital number, since it uses as much as digits as its factorization.

195121639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14580, while the sum is 37.

The square root of 195121639 is about 13968.5947396293. The cubic root of 195121639 is about 580.0095509723.

The spelling of 195121639 in words is "one hundred ninety-five million, one hundred twenty-one thousand, six hundred thirty-nine".