687139487 has 4 divisors (see below), whose sum is σ = 695418360. Its totient is φ = 678860616.

The previous prime is 687139457. The next prime is 687139517. The reversal of 687139487 is 784931786.

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

It is an interprime number because it is at equal distance from previous prime (687139457) and next prime (687139517).

It is a cyclic number.

It is not a de Polignac number, because 687139487 - 2⁶ = 687139423 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 (687139447) 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, 4139312 + ... + 4139477.

It is an arithmetic number, because the mean of its divisors is an integer number (173854590).

Almost surely, 2^687139487 is an apocalyptic number.

687139487 is a deficient number, since it is larger than the sum of its proper divisors (8278873).

687139487 is an equidigital number, since it uses as much as digits as its factorization.

687139487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8278872.

The product of its digits is 2032128, while the sum is 53.

The square root of 687139487 is about 26213.3455896038. The cubic root of 687139487 is about 882.4327857708.

The spelling of 687139487 in words is "six hundred eighty-seven million, one hundred thirty-nine thousand, four hundred eighty-seven".