20405660 has 24 divisors (see below), whose sum is σ = 46748016. Its totient is φ = 7420160.

The previous prime is 20405641. The next prime is 20405663. The reversal of 20405660 is 6650402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20405663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46157 + ... + 46596.

It is an arithmetic number, because the mean of its divisors is an integer number (1947834).

Almost surely, 2^20405660 is an apocalyptic number.

20405660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20405660 is an abundant number, since it is smaller than the sum of its proper divisors (26342356).

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

20405660 is a wasteful number, since it uses less digits than its factorization.

20405660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92773 (or 92771 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 20405660 is about 4517.2624453312. The cubic root of 20405660 is about 273.2647094564.

The spelling of 20405660 in words is "twenty million, four hundred five thousand, six hundred sixty".