3906251981 has 2 divisors, whose sum is σ = 3906251982. Its totient is φ = 3906251980.

The previous prime is 3906251969. The next prime is 3906252011. The reversal of 3906251981 is 1891526093.

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., 3107059081 + 799192900 = 55741^2 + 28270^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3906251981 is a prime.

It is a super-2 number, since 2×3906251981² = 30517609078132848722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3906251941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1953125990 + 1953125991.

It is an arithmetic number, because the mean of its divisors is an integer number (1953125991).

Almost surely, 2^3906251981 is an apocalyptic number.

It is an amenable number.

3906251981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3906251981 is an equidigital number, since it uses as much as digits as its factorization.

3906251981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 3906251981 is about 62500.0158479980. The cubic root of 3906251981 is about 1574.9015785983.

The spelling of 3906251981 in words is "three billion, nine hundred six million, two hundred fifty-one thousand, nine hundred eighty-one".