687939787 has 2 divisors, whose sum is σ = 687939788. Its totient is φ = 687939786.

The previous prime is 687939767. The next prime is 687939839. The reversal of 687939787 is 787939786.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687939787 is a prime.

It is a super-2 number, since 2×687939787² = 946522301075210738, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (687939727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343969893 + 343969894.

It is an arithmetic number, because the mean of its divisors is an integer number (343969894).

Almost surely, 2^687939787 is an apocalyptic number.

687939787 is a deficient number, since it is larger than the sum of its proper divisors (1).

687939787 is an equidigital number, since it uses as much as digits as its factorization.

687939787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32006016, while the sum is 64.

The square root of 687939787 is about 26228.6062725414. The cubic root of 687939787 is about 882.7752378145.

Subtracting 687939787 from its reverse (787939786), we obtain a palindrome (99999999).

The spelling of 687939787 in words is "six hundred eighty-seven million, nine hundred thirty-nine thousand, seven hundred eighty-seven".