20661100 has 36 divisors (see below), whose sum is σ = 45047464. Its totient is φ = 8225280.

The previous prime is 20661049. The next prime is 20661101. The reversal of 20661100 is 116602.

It is not an unprimeable number, because it can be changed into a prime (20661101) 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 11 ways as a sum of consecutive naturals, for example, 30364 + ... + 31036.

Almost surely, 2^20661100 is an apocalyptic number.

20661100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20661100 is an abundant number, since it is smaller than the sum of its proper divisors (24386364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20661100 is a wasteful number, since it uses less digits than its factorization.

20661100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 994 (or 987 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20661100 is about 4545.4482727229. The cubic root of 20661100 is about 274.4002355876.

Adding to 20661100 its reverse (116602), we get a palindrome (20777702).

The spelling of 20661100 in words is "twenty million, six hundred sixty-one thousand, one hundred".