1687648499 has 4 divisors (see below), whose sum is σ = 1687904160. Its totient is φ = 1687392840.

The previous prime is 1687648447. The next prime is 1687648507. The reversal of 1687648499 is 9948467861.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1687648499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1687641499) 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, 117659 + ... + 131220.

It is an arithmetic number, because the mean of its divisors is an integer number (421976040).

Almost surely, 2^1687648499 is an apocalyptic number.

1687648499 is a deficient number, since it is larger than the sum of its proper divisors (255661).

1687648499 is an equidigital number, since it uses as much as digits as its factorization.

1687648499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255660.

The product of its digits is 20901888, while the sum is 62.

The square root of 1687648499 is about 41080.9992453932. Note that the first 3 decimals coincide. The cubic root of 1687648499 is about 1190.5857105398.

Adding to 1687648499 its sum of digits (62), we get a square (1687648561 = 41081²).

The spelling of 1687648499 in words is "one billion, six hundred eighty-seven million, six hundred forty-eight thousand, four hundred ninety-nine".