687780071 has 4 divisors (see below), whose sum is σ = 750305544. Its totient is φ = 625254600.

The previous prime is 687780029. The next prime is 687780073. The reversal of 687780071 is 170087786.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687780071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687780073) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31262720 + ... + 31262741.

It is an arithmetic number, because the mean of its divisors is an integer number (187576386).

Almost surely, 2^687780071 is an apocalyptic number.

687780071 is a deficient number, since it is larger than the sum of its proper divisors (62525473).

687780071 is a wasteful number, since it uses less digits than its factorization.

687780071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62525472.

The product of its (nonzero) digits is 131712, while the sum is 44.

The square root of 687780071 is about 26225.5614048584. The cubic root of 687780071 is about 882.7069158260.

The spelling of 687780071 in words is "six hundred eighty-seven million, seven hundred eighty thousand, seventy-one".