3936215981 has 2 divisors, whose sum is σ = 3936215982. Its totient is φ = 3936215980.

The previous prime is 3936215977. The next prime is 3936215999. The reversal of 3936215981 is 1895126393.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2346918025 + 1589297956 = 48445^2 + 39866^2 .

It is an emirp because it is prime and its reverse (1895126393) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3936215981 - 2² = 3936215977 is a prime.

It is a super-2 number, since 2×3936215981² = 30987592498159584722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3936215971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1968107990 + 1968107991.

It is an arithmetic number, because the mean of its divisors is an integer number (1968107991).

Almost surely, 2^3936215981 is an apocalyptic number.

It is an amenable number.

3936215981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3936215981 is an equidigital number, since it uses as much as digits as its factorization.

3936215981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 47.

The square root of 3936215981 is about 62739.2698475205. The cubic root of 3936215981 is about 1578.9182336472.

The spelling of 3936215981 in words is "three billion, nine hundred thirty-six million, two hundred fifteen thousand, nine hundred eighty-one".