684715620491 has 16 divisors (see below), whose sum is σ = 807804469248. Its totient is φ = 567946231200.

The previous prime is 684715620481. The next prime is 684715620517. The reversal of 684715620491 is 194026517486.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 684715620491 - 2²² = 684711426187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (684715620431) 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, 9908726 + ... + 9977588.

It is an arithmetic number, because the mean of its divisors is an integer number (50487779328).

Almost surely, 2^684715620491 is an apocalyptic number.

684715620491 is a deficient number, since it is larger than the sum of its proper divisors (123088848757).

684715620491 is a wasteful number, since it uses less digits than its factorization.

684715620491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114722.

The product of its (nonzero) digits is 2903040, while the sum is 53.

The spelling of 684715620491 in words is "six hundred eighty-four billion, seven hundred fifteen million, six hundred twenty thousand, four hundred ninety-one".