20661055 has 4 divisors (see below), whose sum is σ = 24793272. Its totient is φ = 16528840.

The previous prime is 20661049. The next prime is 20661101. The reversal of 20661055 is 55016602.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20661055 - 2⁵ = 20661023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2066101 + ... + 2066110.

It is an arithmetic number, because the mean of its divisors is an integer number (6198318).

Almost surely, 2^20661055 is an apocalyptic number.

20661055 is a deficient number, since it is larger than the sum of its proper divisors (4132217).

20661055 is an equidigital number, since it uses as much as digits as its factorization.

20661055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4132216.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 20661055 is about 4545.4433227134. The cubic root of 20661055 is about 274.4000363723.

Adding to 20661055 its reverse (55016602), we get a palindrome (75677657).

The spelling of 20661055 in words is "twenty million, six hundred sixty-one thousand, fifty-five".