20571140 has 12 divisors (see below), whose sum is σ = 43199436. Its totient is φ = 8228448.

The previous prime is 20571137. The next prime is 20571143. The reversal of 20571140 is 4117502.

It is an interprime number because it is at equal distance from previous prime (20571137) and next prime (20571143).

It can be written as a sum of positive squares in 2 ways, for example, as 16144324 + 4426816 = 4018^2 + 2104^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1028557 = 20571140 / (2 + 0 + 5 + 7 + 1 + 1 + 4 + 0).

It is not an unprimeable number, because it can be changed into a prime (20571143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 514259 + ... + 514298.

It is an arithmetic number, because the mean of its divisors is an integer number (3599953).

Almost surely, 2^20571140 is an apocalyptic number.

20571140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20571140 is an abundant number, since it is smaller than the sum of its proper divisors (22628296).

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

20571140 is a wasteful number, since it uses less digits than its factorization.

20571140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1028566 (or 1028564 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 20571140 is about 4535.5418639894. The cubic root of 20571140 is about 274.0014030155.

Adding to 20571140 its reverse (4117502), we get a palindrome (24688642).

The spelling of 20571140 in words is "twenty million, five hundred seventy-one thousand, one hundred forty".