20661910 has 16 divisors (see below), whose sum is σ = 38197296. Its totient is φ = 8041248.

The previous prime is 20661881. The next prime is 20661913. The reversal of 20661910 is 1916602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661913) 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, 27552 + ... + 28291.

It is an arithmetic number, because the mean of its divisors is an integer number (2387331).

Almost surely, 2^20661910 is an apocalyptic number.

20661910 is a deficient number, since it is larger than the sum of its proper divisors (17535386).

20661910 is a wasteful number, since it uses less digits than its factorization.

20661910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55887.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 20661910 is about 4545.5373719726. The cubic root of 20661910 is about 274.4038214129.

The spelling of 20661910 in words is "twenty million, six hundred sixty-one thousand, nine hundred ten".