1660644001 has 3 divisors (see below), whose sum is σ = 1660684753. Its totient is φ = 1660603250.

The previous prime is 1660643987. The next prime is 1660644019. The reversal of 1660644001 is 1004460661.

The square root of 1660644001 is 40751.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1004460661 = 16979 ⋅59159.

It is a de Polignac number, because none of the positive numbers 2^k-1660644001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1660644901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 20376 + ... + 61126.

Almost surely, 2^1660644001 is an apocalyptic number.

1660644001 is the 40751-st square number.

1660644001 is the 20376-th centered octagonal number.

It is an amenable number.

1660644001 is a deficient number, since it is larger than the sum of its proper divisors (40752).

1660644001 is an frugal number, since it uses more digits than its factorization.

1660644001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81502 (or 40751 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The cubic root of 1660644001 is about 1184.2012458570.

The spelling of 1660644001 in words is "one billion, six hundred sixty million, six hundred forty-four thousand, one".