3917981 has 4 divisors (see below), whose sum is σ = 4088352. Its totient is φ = 3747612.

The previous prime is 3917923. The next prime is 3917989. The reversal of 3917981 is 1897193.

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: 1897193 = 41 ⋅46273.

It is a cyclic number.

It is not a de Polignac number, because 3917981 - 2¹⁸ = 3655837 is a prime.

It is a super-2 number, since 2×3917981² = 30701150232722, 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 (3917989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85151 + ... + 85196.

It is an arithmetic number, because the mean of its divisors is an integer number (1022088).

Almost surely, 2^3917981 is an apocalyptic number.

It is an amenable number.

3917981 is a deficient number, since it is larger than the sum of its proper divisors (170371).

3917981 is a wasteful number, since it uses less digits than its factorization.

3917981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170370.

The product of its digits is 13608, while the sum is 38.

The square root of 3917981 is about 1979.3890471557. The cubic root of 3917981 is about 157.6476284410.

The spelling of 3917981 in words is "three million, nine hundred seventeen thousand, nine hundred eighty-one".