1664690687 has 16 divisors (see below), whose sum is σ = 1830090240. Its totient is φ = 1501684800.

The previous prime is 1664690641. The next prime is 1664690689. The reversal of 1664690687 is 7860964661.

It is not a de Polignac number, because 1664690687 - 2¹² = 1664686591 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664690689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 869243 + ... + 871155.

It is an arithmetic number, because the mean of its divisors is an integer number (114380640).

Almost surely, 2^1664690687 is an apocalyptic number.

1664690687 is a deficient number, since it is larger than the sum of its proper divisors (165399553).

1664690687 is a wasteful number, since it uses less digits than its factorization.

1664690687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2494.

The product of its (nonzero) digits is 2612736, while the sum is 53.

The square root of 1664690687 is about 40800.6211594873. The cubic root of 1664690687 is about 1185.1623596132.

The spelling of 1664690687 in words is "one billion, six hundred sixty-four million, six hundred ninety thousand, six hundred eighty-seven".