685533557 has 2 divisors, whose sum is σ = 685533558. Its totient is φ = 685533556.

The previous prime is 685533503. The next prime is 685533559. The reversal of 685533557 is 755335586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 665588401 + 19945156 = 25799^2 + 4466^2 .

It is a cyclic number.

It is not a de Polignac number, because 685533557 - 2⁸ = 685533301 is a prime.

Together with 685533559, 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 (685533559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342766778 + 342766779.

It is an arithmetic number, because the mean of its divisors is an integer number (342766779).

Almost surely, 2^685533557 is an apocalyptic number.

It is an amenable number.

685533557 is a deficient number, since it is larger than the sum of its proper divisors (1).

685533557 is an equidigital number, since it uses as much as digits as its factorization.

685533557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1890000, while the sum is 47.

The square root of 685533557 is about 26182.6957550211. The cubic root of 685533557 is about 881.7447979870.

The spelling of 685533557 in words is "six hundred eighty-five million, five hundred thirty-three thousand, five hundred fifty-seven".