20421051240 has 128 divisors (see below), whose sum is σ = 62330238720. Its totient is φ = 5351270400.

The previous prime is 20421051227. The next prime is 20421051247. The reversal of 20421051240 is 4215012402.

It is not an unprimeable number, because it can be changed into a prime (20421051247) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2697060 + ... + 2704620.

It is an arithmetic number, because the mean of its divisors is an integer number (486954990).

Almost surely, 2^20421051240 is an apocalyptic number.

20421051240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20421051240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31165119360).

20421051240 is an abundant number, since it is smaller than the sum of its proper divisors (41909187480).

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

20421051240 is a wasteful number, since it uses less digits than its factorization.

20421051240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7963 (or 7959 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

Adding to 20421051240 its reverse (4215012402), we get a palindrome (24636063642).

The spelling of 20421051240 in words is "twenty billion, four hundred twenty-one million, fifty-one thousand, two hundred forty".