20531121140 has 12 divisors (see below), whose sum is σ = 43115354436. Its totient is φ = 8212448448.

The previous prime is 20531121131. The next prime is 20531121151. The reversal of 20531121140 is 4112113502.

It can be written as a sum of positive squares in 2 ways, for example, as 6971916004 + 13559205136 = 83498^2 + 116444^2 .

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: 1026556057 = 20531121140 / (2 + 0 + 5 + 3 + 1 + 1 + 2 + 1 + 1 + 4 + 0).

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, 513278009 + ... + 513278048.

It is an arithmetic number, because the mean of its divisors is an integer number (3592946203).

Almost surely, 2^20531121140 is an apocalyptic number.

20531121140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20531121140 is an abundant number, since it is smaller than the sum of its proper divisors (22584233296).

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

20531121140 is a wasteful number, since it uses less digits than its factorization.

20531121140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026556066 (or 1026556064 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 20531121140 its reverse (4112113502), we get a palindrome (24643234642).

The spelling of 20531121140 in words is "twenty billion, five hundred thirty-one million, one hundred twenty-one thousand, one hundred forty".