3971852615691 has 16 divisors (see below), whose sum is σ = 5889989337120. Its totient is φ = 2645308285920.

The previous prime is 3971852615677. The next prime is 3971852615701. The reversal of 3971852615691 is 1965162581793.

3971852615691 is a `hidden beast` number, since 3 + 9 + 7 + 1 + 8 + 5 + 2 + 61 + 569 + 1 = 666.

It is not a de Polignac number, because 3971852615691 - 2²³ = 3971844227083 is a prime.

It is a super-2 number, since 2×3971852615691² (a number of 26 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (3971852615191) 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 15 ways as a sum of consecutive naturals, for example, 72012420 + ... + 72067553.

It is an arithmetic number, because the mean of its divisors is an integer number (368124333570).

Almost surely, 2^{3971852615691} is an apocalyptic number.

3971852615691 is a deficient number, since it is larger than the sum of its proper divisors (1918136721429).

3971852615691 is a wasteful number, since it uses less digits than its factorization.

3971852615691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144081003 (or 144080997 counting only the distinct ones).

The product of its digits is 24494400, while the sum is 63.

The spelling of 3971852615691 in words is "three trillion, nine hundred seventy-one billion, eight hundred fifty-two million, six hundred fifteen thousand, six hundred ninety-one".