21223031580 has 144 divisors (see below), whose sum is σ = 65935125984. Its totient is φ = 5524070400.

The previous prime is 21223031579. The next prime is 21223031587. The reversal of 21223031580 is 8513032212.

21223031580 is a `hidden beast` number, since 2 + 1 + 22 + 30 + 31 + 580 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223031587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1266255 + ... + 1282905.

Almost surely, 2^21223031580 is an apocalyptic number.

21223031580 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 21223031580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32967562992).

21223031580 is an abundant number, since it is smaller than the sum of its proper divisors (44712094404).

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

21223031580 is a wasteful number, since it uses less digits than its factorization.

21223031580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16836 (or 16831 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 21223031580 its reverse (8513032212), we get a palindrome (29736063792).

The spelling of 21223031580 in words is "twenty-one billion, two hundred twenty-three million, thirty-one thousand, five hundred eighty".