687977481781 has 16 divisors (see below), whose sum is σ = 697160149504. Its totient is φ = 678846282624.

The previous prime is 687977481773. The next prime is 687977481833. The reversal of 687977481781 is 187184779786.

It is not a de Polignac number, because 687977481781 - 2³ = 687977481773 is a prime.

It is a super-2 number, since 2×687977481781² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687977481881) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46752481 + ... + 46767193.

It is an arithmetic number, because the mean of its divisors is an integer number (43572509344).

Almost surely, 2^687977481781 is an apocalyptic number.

It is an amenable number.

687977481781 is a deficient number, since it is larger than the sum of its proper divisors (9182667723).

687977481781 is a wasteful number, since it uses less digits than its factorization.

687977481781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16420.

The product of its digits is 265531392, while the sum is 73.

The spelling of 687977481781 in words is "six hundred eighty-seven billion, nine hundred seventy-seven million, four hundred eighty-one thousand, seven hundred eighty-one".