684140791 has 2 divisors, whose sum is σ = 684140792. Its totient is φ = 684140790.

The previous prime is 684140731. The next prime is 684140797. The reversal of 684140791 is 197041486.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 684140791 - 2⁹ = 684140279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684140797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342070395 + 342070396.

It is an arithmetic number, because the mean of its divisors is an integer number (342070396).

Almost surely, 2^684140791 is an apocalyptic number.

684140791 is a deficient number, since it is larger than the sum of its proper divisors (1).

684140791 is an equidigital number, since it uses as much as digits as its factorization.

684140791 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 684140791 is about 26156.0851619657. The cubic root of 684140791 is about 881.1472601182.

The spelling of 684140791 in words is "six hundred eighty-four million, one hundred forty thousand, seven hundred ninety-one".