3971265781 has 8 divisors (see below), whose sum is σ = 4649287104. Its totient is φ = 3320918880.

The previous prime is 3971265667. The next prime is 3971265797. The reversal of 3971265781 is 1875621793.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 3971265781 - 2⁹ = 3971265269 is a prime.

It is a super-2 number, since 2×3971265781² = 31541903806683079922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3971205781) 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 7 ways as a sum of consecutive naturals, for example, 6918295 + ... + 6918868.

It is an arithmetic number, because the mean of its divisors is an integer number (581160888).

Almost surely, 2^3971265781 is an apocalyptic number.

It is an amenable number.

3971265781 is a deficient number, since it is larger than the sum of its proper divisors (678021323).

3971265781 is a wasteful number, since it uses less digits than its factorization.

3971265781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13837211.

The product of its digits is 635040, while the sum is 49.

The square root of 3971265781 is about 63017.9798232219. The cubic root of 3971265781 is about 1583.5908529712.

The spelling of 3971265781 in words is "three billion, nine hundred seventy-one million, two hundred sixty-five thousand, seven hundred eighty-one".