685537537577 has 2 divisors, whose sum is σ = 685537537578. Its totient is φ = 685537537576.

The previous prime is 685537537561. The next prime is 685537537583. The reversal of 685537537577 is 775735735586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 411861031696 + 273676505881 = 641764^2 + 523141^2 .

It is a cyclic number.

It is not a de Polignac number, because 685537537577 - 2⁴ = 685537537561 is a prime.

It is a super-3 number, since 3×685537537577³ (a number of 36 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (685537537537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342768768788 + 342768768789.

It is an arithmetic number, because the mean of its divisors is an integer number (342768768789).

Almost surely, 2^685537537577 is an apocalyptic number.

It is an amenable number.

685537537577 is a deficient number, since it is larger than the sum of its proper divisors (1).

685537537577 is an equidigital number, since it uses as much as digits as its factorization.

685537537577 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648270000, while the sum is 68.

The spelling of 685537537577 in words is "six hundred eighty-five billion, five hundred thirty-seven million, five hundred thirty-seven thousand, five hundred seventy-seven".