687155869 has 2 divisors, whose sum is σ = 687155870. Its totient is φ = 687155868.

The previous prime is 687155747. The next prime is 687155891. The reversal of 687155869 is 968551786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 659719225 + 27436644 = 25685^2 + 5238^2 .

It is a cyclic number.

It is not a de Polignac number, because 687155869 - 2⁷ = 687155741 is a prime.

It is a super-2 number, since 2×687155869² = 944366376602290322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687155569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343577934 + 343577935.

It is an arithmetic number, because the mean of its divisors is an integer number (343577935).

Almost surely, 2^687155869 is an apocalyptic number.

It is an amenable number.

687155869 is a deficient number, since it is larger than the sum of its proper divisors (1).

687155869 is an equidigital number, since it uses as much as digits as its factorization.

687155869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3628800, while the sum is 55.

The square root of 687155869 is about 26213.6580621629. The cubic root of 687155869 is about 882.4397983688.

The spelling of 687155869 in words is "six hundred eighty-seven million, one hundred fifty-five thousand, eight hundred sixty-nine".