20660661 has 48 divisors (see below), whose sum is σ = 36661248. Its totient is φ = 10944000.

The previous prime is 20660659. The next prime is 20660669. The reversal of 20660661 is 16606602.

It is not a de Polignac number, because 20660661 - 2¹ = 20660659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20660669) 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 47 ways as a sum of consecutive naturals, for example, 108076 + ... + 108266.

It is an arithmetic number, because the mean of its divisors is an integer number (763776).

Almost surely, 2^20660661 is an apocalyptic number.

20660661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20660661 is a deficient number, since it is larger than the sum of its proper divisors (16000587).

20660661 is a wasteful number, since it uses less digits than its factorization.

20660661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322 (or 319 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 20660661 is about 4545.3999823998. The cubic root of 20660661 is about 274.3982921196.

It can be divided in two parts, 20660 and 661, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 20660661 in words is "twenty million, six hundred sixty thousand, six hundred sixty-one".