20664661 has 8 divisors (see below), whose sum is σ = 20916000. Its totient is φ = 20415120.

The previous prime is 20664659. The next prime is 20664667. The reversal of 20664661 is 16646602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20664661 - 2¹ = 20664659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20664667) 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 7 ways as a sum of consecutive naturals, for example, 49110 + ... + 49528.

It is an arithmetic number, because the mean of its divisors is an integer number (2614500).

Almost surely, 2^20664661 is an apocalyptic number.

It is an amenable number.

20664661 is a deficient number, since it is larger than the sum of its proper divisors (251339).

20664661 is a wasteful number, since it uses less digits than its factorization.

20664661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 899.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 20664661 is about 4545.8399663869. The cubic root of 20664661 is about 274.4159992385.

The spelling of 20664661 in words is "twenty million, six hundred sixty-four thousand, six hundred sixty-one".