20131560 has 48 divisors (see below), whose sum is σ = 65428740. Its totient is φ = 5368320.

The previous prime is 20131549. The next prime is 20131561. The reversal of 20131560 is 6513102.

It can be written as a sum of positive squares in 2 ways, for example, as 18818244 + 1313316 = 4338^2 + 1146^2 .

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 (20131561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27601 + ... + 28320.

Almost surely, 2^20131560 is an apocalyptic number.

20131560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20131560 is an abundant number, since it is smaller than the sum of its proper divisors (45297180).

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

20131560 is a wasteful number, since it uses less digits than its factorization.

20131560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55938 (or 55931 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 20131560 is about 4486.8207006744. The cubic root of 20131560 is about 272.0356426764.

Adding to 20131560 its reverse (6513102), we get a palindrome (26644662).

The spelling of 20131560 in words is "twenty million, one hundred thirty-one thousand, five hundred sixty".