20664001 has 6 divisors (see below), whose sum is σ = 21809202. Its totient is φ = 19576080.

The previous prime is 20663989. The next prime is 20664013. The reversal of 20664001 is 10046602.

It is an interprime number because it is at equal distance from previous prime (20663989) and next prime (20664013).

It can be written as a sum of positive squares in only one way, i.e., 15023376 + 5640625 = 3876^2 + 2375^2 .

It is not a de Polignac number, because 20664001 - 2⁵ = 20663969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20664001.

It is not an unprimeable number, because it can be changed into a prime (20664031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 28260 + ... + 28981.

It is an arithmetic number, because the mean of its divisors is an integer number (3634867).

Almost surely, 2^20664001 is an apocalyptic number.

20664001 is the 2625-th hex number.

It is an amenable number.

20664001 is a deficient number, since it is larger than the sum of its proper divisors (1145201).

20664001 is an equidigital number, since it uses as much as digits as its factorization.

20664001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57279 (or 57260 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 20664001 is about 4545.7673719626. The cubic root of 20664001 is about 274.4130777213.

The spelling of 20664001 in words is "twenty million, six hundred sixty-four thousand, one".