687819811 has 6 divisors (see below), whose sum is σ = 800116980. Its totient is φ = 589559796.

The previous prime is 687819809. The next prime is 687819827. The reversal of 687819811 is 118918786.

It is not a de Polignac number, because 687819811 - 2¹ = 687819809 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 14037139 = 687819811 / (6 + 8 + 7 + 8 + 1 + 9 + 8 + 1 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (687819311) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7018521 + ... + 7018618.

It is an arithmetic number, because the mean of its divisors is an integer number (133352830).

Almost surely, 2^687819811 is an apocalyptic number.

687819811 is a deficient number, since it is larger than the sum of its proper divisors (112297169).

687819811 is a wasteful number, since it uses less digits than its factorization.

687819811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14037153 (or 14037146 counting only the distinct ones).

The product of its digits is 193536, while the sum is 49.

The square root of 687819811 is about 26226.3190516702. The cubic root of 687819811 is about 882.7239164627.

The spelling of 687819811 in words is "six hundred eighty-seven million, eight hundred nineteen thousand, eight hundred eleven".