20731140 has 120 divisors (see below), whose sum is σ = 66350592. Its totient is φ = 5417280.

The previous prime is 20731133. The next prime is 20731153. The reversal of 20731140 is 4113702.

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

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 108445 + ... + 108635.

Almost surely, 2^20731140 is an apocalyptic number.

20731140 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 20731140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33175296).

20731140 is an abundant number, since it is smaller than the sum of its proper divisors (45619452).

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

20731140 is a wasteful number, since it uses less digits than its factorization.

20731140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 20731140 is about 4553.1461650160. The cubic root of 20731140 is about 274.7099531437.

Adding to 20731140 its reverse (4113702), we get a palindrome (24844842).

The spelling of 20731140 in words is "twenty million, seven hundred thirty-one thousand, one hundred forty".