20421525540 has 96 divisors (see below), whose sum is σ = 61646409216. Its totient is φ = 5021314560.

The previous prime is 20421525539. The next prime is 20421525547. The reversal of 20421525540 is 4552512402.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20421525498 and 20421525507.

It is not an unprimeable number, because it can be changed into a prime (20421525547) 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 31 ways as a sum of consecutive naturals, for example, 720069 + ... + 747891.

It is an arithmetic number, because the mean of its divisors is an integer number (642150096).

Almost surely, 2^20421525540 is an apocalyptic number.

20421525540 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 20421525540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30823204608).

20421525540 is an abundant number, since it is smaller than the sum of its proper divisors (41224883676).

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

20421525540 is a wasteful number, since it uses less digits than its factorization.

20421525540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28789 (or 28787 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 30.

The spelling of 20421525540 in words is "twenty billion, four hundred twenty-one million, five hundred twenty-five thousand, five hundred forty".