3991523687961 has 8 divisors (see below), whose sum is σ = 5322465624000. Its totient is φ = 2660798771952.

The previous prime is 3991523687953. The next prime is 3991523687993. The reversal of 3991523687961 is 1697863251993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3991523687961 - 2³ = 3991523687953 is a prime.

It is a super-2 number, since 2×3991523687961² (a number of 26 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (3991523677961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54212086 + ... + 54285663.

It is an arithmetic number, because the mean of its divisors is an integer number (665308203000).

Almost surely, 2^{3991523687961} is an apocalyptic number.

It is an amenable number.

3991523687961 is a deficient number, since it is larger than the sum of its proper divisors (1330941936039).

3991523687961 is a wasteful number, since it uses less digits than its factorization.

3991523687961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108510015.

The product of its digits is 132269760, while the sum is 69.

The spelling of 3991523687961 in words is "three trillion, nine hundred ninety-one billion, five hundred twenty-three million, six hundred eighty-seven thousand, nine hundred sixty-one".