687055621 has 4 divisors (see below), whose sum is σ = 785206432. Its totient is φ = 588904812.

The previous prime is 687055619. The next prime is 687055651. The reversal of 687055621 is 126550786.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 687055621 - 2¹ = 687055619 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 (687055651) 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, 49075395 + ... + 49075408.

It is an arithmetic number, because the mean of its divisors is an integer number (196301608).

Almost surely, 2^687055621 is an apocalyptic number.

It is an amenable number.

687055621 is a deficient number, since it is larger than the sum of its proper divisors (98150811).

687055621 is an equidigital number, since it uses as much as digits as its factorization.

687055621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98150810.

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 687055621 is about 26211.7458594425. The cubic root of 687055621 is about 882.3968837351.

The spelling of 687055621 in words is "six hundred eighty-seven million, fifty-five thousand, six hundred twenty-one".