7678661 has 2 divisors, whose sum is σ = 7678662. Its totient is φ = 7678660.

The previous prime is 7678637. The next prime is 7678663. The reversal of 7678661 is 1668767.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5909761 + 1768900 = 2431^2 + 1330^2 .

It is a cyclic number.

It is not a de Polignac number, because 7678661 - 2⁶ = 7678597 is a prime.

Together with 7678663, 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 (7678663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3839330 + 3839331.

It is an arithmetic number, because the mean of its divisors is an integer number (3839331).

Almost surely, 2^7678661 is an apocalyptic number.

It is an amenable number.

7678661 is a deficient number, since it is larger than the sum of its proper divisors (1).

7678661 is an equidigital number, since it uses as much as digits as its factorization.

7678661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 41.

The square root of 7678661 is about 2771.0396965760. The cubic root of 7678661 is about 197.2854991065.

The spelling of 7678661 in words is "seven million, six hundred seventy-eight thousand, six hundred sixty-one".