3930781 has 4 divisors (see below), whose sum is σ = 3959200. Its totient is φ = 3902364.

The previous prime is 3930767. The next prime is 3930799. The reversal of 3930781 is 1870393.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1870393 = 7 ⋅267199.

It is a cyclic number.

It is not a de Polignac number, because 3930781 - 2⁷ = 3930653 is a prime.

It is a super-2 number, since 2×3930781² = 30902078539922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3930721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14001 + ... + 14278.

It is an arithmetic number, because the mean of its divisors is an integer number (989800).

Almost surely, 2^3930781 is an apocalyptic number.

It is an amenable number.

3930781 is a deficient number, since it is larger than the sum of its proper divisors (28419).

3930781 is a wasteful number, since it uses less digits than its factorization.

3930781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28418.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 3930781 is about 1982.6197315673. The cubic root of 3930781 is about 157.8191195014.

The spelling of 3930781 in words is "three million, nine hundred thirty thousand, seven hundred eighty-one".