20471540 has 12 divisors (see below), whose sum is σ = 42990276. Its totient is φ = 8188608.

The previous prime is 20471497. The next prime is 20471579. The reversal of 20471540 is 4517402.

It can be written as a sum of positive squares in 2 ways, for example, as 8596624 + 11874916 = 2932^2 + 3446^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 511769 + ... + 511808.

It is an arithmetic number, because the mean of its divisors is an integer number (3582523).

Almost surely, 2^20471540 is an apocalyptic number.

20471540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20471540 is an abundant number, since it is smaller than the sum of its proper divisors (22518736).

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

20471540 is a wasteful number, since it uses less digits than its factorization.

20471540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1023586 (or 1023584 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 20471540 is about 4524.5485962690. The cubic root of 20471540 is about 273.5584733721.

Adding to 20471540 its reverse (4517402), we get a palindrome (24988942).

The spelling of 20471540 in words is "twenty million, four hundred seventy-one thousand, five hundred forty".