20121234540 has 48 divisors (see below), whose sum is σ = 61461227520. Its totient is φ = 4877874880.

The previous prime is 20121234533. The next prime is 20121234557. The reversal of 20121234540 is 4543212102.

It is a self number, because there is not a number n which added to its sum of digits gives 20121234540.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15242700 + ... + 15244019.

It is an arithmetic number, because the mean of its divisors is an integer number (1280442240).

Almost surely, 2^20121234540 is an apocalyptic number.

20121234540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20121234540 is an abundant number, since it is smaller than the sum of its proper divisors (41339992980).

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

20121234540 is a wasteful number, since it uses less digits than its factorization.

20121234540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30486742 (or 30486740 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

Adding to 20121234540 its reverse (4543212102), we get a palindrome (24664446642).

The spelling of 20121234540 in words is "twenty billion, one hundred twenty-one million, two hundred thirty-four thousand, five hundred forty".