686622621 has 4 divisors (see below), whose sum is σ = 915496832. Its totient is φ = 457748412.

The previous prime is 686622619. The next prime is 686622631. The reversal of 686622621 is 126226686.

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 not a de Polignac number, because 686622621 - 2¹ = 686622619 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 686622621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686622631) 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, 114437101 + ... + 114437106.

It is an arithmetic number, because the mean of its divisors is an integer number (228874208).

Almost surely, 2^686622621 is an apocalyptic number.

It is an amenable number.

686622621 is a deficient number, since it is larger than the sum of its proper divisors (228874211).

686622621 is a wasteful number, since it uses less digits than its factorization.

686622621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228874210.

The product of its digits is 82944, while the sum is 39.

The square root of 686622621 is about 26203.4849018217. The cubic root of 686622621 is about 882.2114750956.

The spelling of 686622621 in words is "six hundred eighty-six million, six hundred twenty-two thousand, six hundred twenty-one".