20821240080 has 160 divisors (see below), whose sum is σ = 71777310720. Its totient is φ = 5547709440.

The previous prime is 20821240031. The next prime is 20821240081. The reversal of 20821240080 is 8004212802.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20821240081) 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, 3174084 + ... + 3180636.

It is an arithmetic number, because the mean of its divisors is an integer number (448608192).

Almost surely, 2^20821240080 is an apocalyptic number.

20821240080 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 20821240080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35888655360).

20821240080 is an abundant number, since it is smaller than the sum of its proper divisors (50956070640).

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

20821240080 is a wasteful number, since it uses less digits than its factorization.

20821240080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8046 (or 8034 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

Adding to 20821240080 its reverse (8004212802), we get a palindrome (28825452882).

The spelling of 20821240080 in words is "twenty billion, eight hundred twenty-one million, two hundred forty thousand, eighty".