21575042280 has 256 divisors, whose sum is σ = 79235884800. Its totient is φ = 5178240000.

The previous prime is 21575042273. The next prime is 21575042299. The reversal of 21575042280 is 8224057512.

It is a happy number.

21575042280 is a `hidden beast` number, since 2 + 1 + 57 + 504 + 22 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1190890 + ... + 1208870.

It is an arithmetic number, because the mean of its divisors is an integer number (309515175).

Almost surely, 2^21575042280 is an apocalyptic number.

21575042280 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 21575042280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39617942400).

21575042280 is an abundant number, since it is smaller than the sum of its proper divisors (57660842520).

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

21575042280 is a wasteful number, since it uses less digits than its factorization.

21575042280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18113 (or 18103 counting only the distinct ones).

The product of its (nonzero) digits is 44800, while the sum is 36.

Adding to 21575042280 its reverse (8224057512), we get a palindrome (29799099792).

The spelling of 21575042280 in words is "twenty-one billion, five hundred seventy-five million, forty-two thousand, two hundred eighty".