687428887621 has 16 divisors (see below), whose sum is σ = 796448024064. Its totient is φ = 581114577024.

The previous prime is 687428887619. The next prime is 687428887633. The reversal of 687428887621 is 126788824786.

It is a cyclic number.

It is not a de Polignac number, because 687428887621 - 2¹ = 687428887619 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687428287621) 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, 9754116 + ... + 9824338.

It is an arithmetic number, because the mean of its divisors is an integer number (49778001504).

Almost surely, 2^687428887621 is an apocalyptic number.

It is an amenable number.

687428887621 is a deficient number, since it is larger than the sum of its proper divisors (109019136443).

687428887621 is a wasteful number, since it uses less digits than its factorization.

687428887621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89460.

The product of its digits is 115605504, while the sum is 67.

The spelling of 687428887621 in words is "six hundred eighty-seven billion, four hundred twenty-eight million, eight hundred eighty-seven thousand, six hundred twenty-one".