7978381 has 2 divisors, whose sum is σ = 7978382. Its totient is φ = 7978380.

The previous prime is 7978379. The next prime is 7978403. The reversal of 7978381 is 1838797.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6375625 + 1602756 = 2525^2 + 1266^2 .

It is a cyclic number.

It is not a de Polignac number, because 7978381 - 2¹ = 7978379 is a prime.

It is a super-2 number, since 2×7978381² = 127309126762322, which contains 22 as substring.

Together with 7978379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7978301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3989190 + 3989191.

It is an arithmetic number, because the mean of its divisors is an integer number (3989191).

Almost surely, 2^7978381 is an apocalyptic number.

It is an amenable number.

7978381 is a deficient number, since it is larger than the sum of its proper divisors (1).

7978381 is an equidigital number, since it uses as much as digits as its factorization.

7978381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84672, while the sum is 43.

The square root of 7978381 is about 2824.6028039354. The cubic root of 7978381 is about 199.8196791375.

The spelling of 7978381 in words is "seven million, nine hundred seventy-eight thousand, three hundred eighty-one".