20661172 has 24 divisors (see below), whose sum is σ = 41791680. Its totient is φ = 8754240.

The previous prime is 20661143. The next prime is 20661191. The reversal of 20661172 is 27116602.

It is a congruent number.

It is an unprimeable number.

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, 1654 + ... + 6637.

It is an arithmetic number, because the mean of its divisors is an integer number (1741320).

Almost surely, 2^20661172 is an apocalyptic number.

It is an amenable number.

20661172 is an abundant number, since it is smaller than the sum of its proper divisors (21130508).

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

20661172 is a wasteful number, since it uses less digits than its factorization.

20661172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8391 (or 8389 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 20661172 is about 4545.4561927270. The cubic root of 20661172 is about 274.4005543314.

Adding to 20661172 its reverse (27116602), we get a palindrome (47777774).

The spelling of 20661172 in words is "twenty million, six hundred sixty-one thousand, one hundred seventy-two".