3988781 has 2 divisors, whose sum is σ = 3988782. Its totient is φ = 3988780.

The previous prime is 3988771. The next prime is 3988783. The reversal of 3988781 is 1878893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3455881 + 532900 = 1859^2 + 730^2 .

It is a cyclic number.

It is not a de Polignac number, because 3988781 - 2⁶ = 3988717 is a prime.

It is a super-2 number, since 2×3988781² = 31820747731922, which contains 22 as substring.

Together with 3988783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3988783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1994390 + 1994391.

It is an arithmetic number, because the mean of its divisors is an integer number (1994391).

Almost surely, 2^3988781 is an apocalyptic number.

It is an amenable number.

3988781 is a deficient number, since it is larger than the sum of its proper divisors (1).

3988781 is an equidigital number, since it uses as much as digits as its factorization.

3988781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 44.

The square root of 3988781 is about 1997.1932805815. The cubic root of 3988781 is about 158.5915574604.

The spelling of 3988781 in words is "three million, nine hundred eighty-eight thousand, seven hundred eighty-one".