1687665537 has 20 divisors (see below), whose sum is σ = 2522414400. Its totient is φ = 1124515224.

The previous prime is 1687665523. The next prime is 1687665541. The reversal of 1687665537 is 7355667861.

1687665537 is a `hidden beast` number, since 1 + 6 + 87 + 6 + 6 + 553 + 7 = 666.

It is not a de Polignac number, because 1687665537 - 2⁷ = 1687665409 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

Its product of digits (6350400) is a multiple of the sum of its prime divisors (11025).

It is not an unprimeable number, because it can be changed into a prime (1687665137) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 191964 + ... + 200562.

It is an arithmetic number, because the mean of its divisors is an integer number (126120720).

Almost surely, 2^1687665537 is an apocalyptic number.

It is an amenable number.

1687665537 is a deficient number, since it is larger than the sum of its proper divisors (834748863).

1687665537 is an equidigital number, since it uses as much as digits as its factorization.

1687665537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11034 (or 11025 counting only the distinct ones).

The product of its digits is 6350400, while the sum is 54.

The square root of 1687665537 is about 41081.2066156777. The cubic root of 1687665537 is about 1190.5897171267.

The spelling of 1687665537 in words is "one billion, six hundred eighty-seven million, six hundred sixty-five thousand, five hundred thirty-seven".