1995915721391 has 4 divisors (see below), whose sum is σ = 1995962569272. Its totient is φ = 1995868873512.

The previous prime is 1995915721381. The next prime is 1995915721411. The reversal of 1995915721391 is 1931275195991.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1995915721391 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 (1995915721301) 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, 23359976 + ... + 23445261.

It is an arithmetic number, because the mean of its divisors is an integer number (498990642318).

Almost surely, 2^{1995915721391} is an apocalyptic number.

1995915721391 is a deficient number, since it is larger than the sum of its proper divisors (46847881).

1995915721391 is an equidigital number, since it uses as much as digits as its factorization.

1995915721391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46847880.

The product of its digits is 6889050, while the sum is 62.

The spelling of 1995915721391 in words is "one trillion, nine hundred ninety-five billion, nine hundred fifteen million, seven hundred twenty-one thousand, three hundred ninety-one".