3991620173899 has 4 divisors (see below), whose sum is σ = 4165168877136. Its totient is φ = 3818071470664.

The previous prime is 3991620173897. The next prime is 3991620173963. The reversal of 3991620173899 is 9983710261993.

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

It is a cyclic number.

It is not a de Polignac number, because 3991620173899 - 2¹ = 3991620173897 is a prime.

It is a super-2 number, since 2×3991620173899² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3991620173897) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 86774351584 + ... + 86774351629.

It is an arithmetic number, because the mean of its divisors is an integer number (1041292219284).

Almost surely, 2^{3991620173899} is an apocalyptic number.

3991620173899 is a deficient number, since it is larger than the sum of its proper divisors (173548703237).

3991620173899 is a wasteful number, since it uses less digits than its factorization.

3991620173899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173548703236.

The product of its (nonzero) digits is 39680928, while the sum is 67.

The spelling of 3991620173899 in words is "three trillion, nine hundred ninety-one billion, six hundred twenty million, one hundred seventy-three thousand, eight hundred ninety-nine".