3991621231672 has 16 divisors (see below), whose sum is σ = 7487232942240. Its totient is φ = 1995025780416.

The previous prime is 3991621231649. The next prime is 3991621231723. The reversal of 3991621231672 is 2761321261993.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98082813 + ... + 98123500.

It is an arithmetic number, because the mean of its divisors is an integer number (467952058890).

Almost surely, 2^{3991621231672} is an apocalyptic number.

It is an amenable number.

3991621231672 is a deficient number, since it is larger than the sum of its proper divisors (3495611710568).

3991621231672 is a wasteful number, since it uses less digits than its factorization.

3991621231672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196208862 (or 196208858 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 52.

The spelling of 3991621231672 in words is "three trillion, nine hundred ninety-one billion, six hundred twenty-one million, two hundred thirty-one thousand, six hundred seventy-two".