3981511217 has 2 divisors, whose sum is σ = 3981511218. Its totient is φ = 3981511216.

The previous prime is 3981511213. The next prime is 3981511241. The reversal of 3981511217 is 7121151893.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2705664256 + 1275846961 = 52016^2 + 35719^2 .

It is a cyclic number.

It is not a de Polignac number, because 3981511217 - 2² = 3981511213 is a prime.

It is not a weakly prime, because it can be changed into another prime (3981511213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1990755608 + 1990755609.

It is an arithmetic number, because the mean of its divisors is an integer number (1990755609).

Almost surely, 2^3981511217 is an apocalyptic number.

It is an amenable number.

3981511217 is a deficient number, since it is larger than the sum of its proper divisors (1).

3981511217 is an equidigital number, since it uses as much as digits as its factorization.

3981511217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 38.

The square root of 3981511217 is about 63099.2172455412. The cubic root of 3981511217 is about 1584.9515145368.

The spelling of 3981511217 in words is "three billion, nine hundred eighty-one million, five hundred eleven thousand, two hundred seventeen".