687978642097 has 2 divisors, whose sum is σ = 687978642098. Its totient is φ = 687978642096.

The previous prime is 687978642083. The next prime is 687978642101. The reversal of 687978642097 is 790246879786.

687978642097 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 499070189601 + 188908452496 = 706449^2 + 434636^2 .

It is a cyclic number.

It is not a de Polignac number, because 687978642097 - 2⁷ = 687978641969 is a prime.

It is a super-2 number, since 2×687978642097² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (687978642067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343989321048 + 343989321049.

It is an arithmetic number, because the mean of its divisors is an integer number (343989321049).

Almost surely, 2^687978642097 is an apocalyptic number.

It is an amenable number.

687978642097 is a deficient number, since it is larger than the sum of its proper divisors (1).

687978642097 is an equidigital number, since it uses as much as digits as its factorization.

687978642097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512096256, while the sum is 73.

The spelling of 687978642097 in words is "six hundred eighty-seven billion, nine hundred seventy-eight million, six hundred forty-two thousand, ninety-seven".