20704140 has 96 divisors (see below), whose sum is σ = 67253760. Its totient is φ = 5277888.

The previous prime is 20704093. The next prime is 20704141. The reversal of 20704140 is 4140702.

It is a happy number.

It is a super-2 number, since 2×20704140² = 857322826279200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (20704141) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11587 + ... + 13253.

It is an arithmetic number, because the mean of its divisors is an integer number (700560).

Almost surely, 2^20704140 is an apocalyptic number.

20704140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20704140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33626880).

20704140 is an abundant number, since it is smaller than the sum of its proper divisors (46549620).

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

20704140 is a wasteful number, since it uses less digits than its factorization.

20704140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1708 (or 1700 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 20704140 is about 4550.1802162112. The cubic root of 20704140 is about 274.5906416301.

Adding to 20704140 its reverse (4140702), we get a palindrome (24844842).

The spelling of 20704140 in words is "twenty million, seven hundred four thousand, one hundred forty".