20664587 has 2 divisors, whose sum is σ = 20664588. Its totient is φ = 20664586.

The previous prime is 20664529. The next prime is 20664601. The reversal of 20664587 is 78546602.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20664587 - 2¹⁸ = 20402443 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20664587.

It is not a weakly prime, because it can be changed into another prime (20660587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332293 + 10332294.

It is an arithmetic number, because the mean of its divisors is an integer number (10332294).

Almost surely, 2^20664587 is an apocalyptic number.

20664587 is a deficient number, since it is larger than the sum of its proper divisors (1).

20664587 is an equidigital number, since it uses as much as digits as its factorization.

20664587 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 38.

The square root of 20664587 is about 4545.8318270697. The cubic root of 20664587 is about 274.4156716776.

The spelling of 20664587 in words is "twenty million, six hundred sixty-four thousand, five hundred eighty-seven".