195721191645 has 16 divisors (see below), whose sum is σ = 357890179200. Its totient is φ = 89472544704.

The previous prime is 195721191619. The next prime is 195721191683. The reversal of 195721191645 is 546191127591.

195721191645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 195721191645 - 2⁶ = 195721191581 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 932005570 + ... + 932005779.

It is an arithmetic number, because the mean of its divisors is an integer number (22368136200).

Almost surely, 2^195721191645 is an apocalyptic number.

195721191645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

195721191645 is a deficient number, since it is larger than the sum of its proper divisors (162168987555).

195721191645 is a wasteful number, since it uses less digits than its factorization.

195721191645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1864011364.

The product of its digits is 680400, while the sum is 51.

The spelling of 195721191645 in words is "one hundred ninety-five billion, seven hundred twenty-one million, one hundred ninety-one thousand, six hundred forty-five".