21024155880 has 1024 divisors, whose sum is σ = 92574720000. Its totient is φ = 4172166144.

The previous prime is 21024155837. The next prime is 21024155903. The reversal of 21024155880 is 8855142012.

21024155880 is a `hidden beast` number, since 2 + 1 + 0 + 24 + 1 + 558 + 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 255 ways as a sum of consecutive naturals, for example, 151252851 + ... + 151252989.

It is an arithmetic number, because the mean of its divisors is an integer number (90405000).

Almost surely, 2^21024155880 is an apocalyptic number.

21024155880 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 21024155880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46287360000).

21024155880 is an abundant number, since it is smaller than the sum of its proper divisors (71550564120).

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

21024155880 is a wasteful number, since it uses less digits than its factorization.

21024155880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 36.

Adding to 21024155880 its reverse (8855142012), we get a palindrome (29879297892).

The spelling of 21024155880 in words is "twenty-one billion, twenty-four million, one hundred fifty-five thousand, eight hundred eighty".