678749 has 2 divisors, whose sum is σ = 678750. Its totient is φ = 678748.

The previous prime is 678739. The next prime is 678757. The reversal of 678749 is 947876.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 592900 + 85849 = 770^2 + 293^2 .

It is a cyclic number.

It is not a de Polignac number, because 678749 - 2⁸ = 678493 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339374 + 339375.

It is an arithmetic number, because the mean of its divisors is an integer number (339375).

2⁶⁷⁸⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

678749 is a deficient number, since it is larger than the sum of its proper divisors (1).

678749 is an equidigital number, since it uses as much as digits as its factorization.

678749 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 678749 is about 823.8622457669. The cubic root of 678749 is about 87.8826345174.

The spelling of 678749 in words is "six hundred seventy-eight thousand, seven hundred forty-nine".