1686457121 has 4 divisors (see below), whose sum is σ = 1715041200. Its totient is φ = 1657873044.

The previous prime is 1686457109. The next prime is 1686457139. The reversal of 1686457121 is 1217546861.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1217546861 = 3067 ⋅396983.

It is a cyclic number.

It is not a de Polignac number, because 1686457121 - 2¹⁴ = 1686440737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1686457321) 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, 14291951 + ... + 14292068.

It is an arithmetic number, because the mean of its divisors is an integer number (428760300).

Almost surely, 2^1686457121 is an apocalyptic number.

It is an amenable number.

1686457121 is a deficient number, since it is larger than the sum of its proper divisors (28584079).

1686457121 is an equidigital number, since it uses as much as digits as its factorization.

1686457121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28584078.

The product of its digits is 80640, while the sum is 41.

The square root of 1686457121 is about 41066.4963321684. The cubic root of 1686457121 is about 1190.3054840330.

The spelling of 1686457121 in words is "one billion, six hundred eighty-six million, four hundred fifty-seven thousand, one hundred twenty-one".