3918391 has 2 divisors, whose sum is σ = 3918392. Its totient is φ = 3918390.

The previous prime is 3918379. The next prime is 3918401. The reversal of 3918391 is 1938193.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 3918391 - 2⁵ = 3918359 is a prime.

3918391 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3918301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1959195 + 1959196.

It is an arithmetic number, because the mean of its divisors is an integer number (1959196).

Almost surely, 2^3918391 is an apocalyptic number.

3918391 is a deficient number, since it is larger than the sum of its proper divisors (1).

3918391 is an equidigital number, since it uses as much as digits as its factorization.

3918391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 34.

The square root of 3918391 is about 1979.4926117569. The cubic root of 3918391 is about 157.6531272998.

It can be divided in two parts, 39183 and 91, that multiplied together give a palindrome (3565653).

The spelling of 3918391 in words is "three million, nine hundred eighteen thousand, three hundred ninety-one".