1664684571 has 16 divisors (see below), whose sum is σ = 2461056768. Its totient is φ = 992359200.

The previous prime is 1664684513. The next prime is 1664684573. The reversal of 1664684571 is 1754864661.

It is a happy number.

It is not a de Polignac number, because 1664684571 - 2⁷ = 1664684443 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1664684571.

It is not an unprimeable number, because it can be changed into a prime (1664684573) 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, 411471 + ... + 415496.

It is an arithmetic number, because the mean of its divisors is an integer number (153816048).

Almost surely, 2^1664684571 is an apocalyptic number.

1664684571 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1664684571 is a deficient number, since it is larger than the sum of its proper divisors (796372197).

1664684571 is a wasteful number, since it uses less digits than its factorization.

1664684571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827042.

The product of its digits is 967680, while the sum is 48.

The square root of 1664684571 is about 40800.5462095791. The cubic root of 1664684571 is about 1185.1609082001.

The spelling of 1664684571 in words is "one billion, six hundred sixty-four million, six hundred eighty-four thousand, five hundred seventy-one".