21193521220 has 12 divisors (see below), whose sum is σ = 44506394604. Its totient is φ = 8477408480.

The previous prime is 21193521187. The next prime is 21193521221. The reversal of 21193521220 is 2212539112.

It can be written as a sum of positive squares in 2 ways, for example, as 13448113156 + 7745408064 = 115966^2 + 88008^2 .

It is not an unprimeable number, because it can be changed into a prime (21193521221) 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 3 ways as a sum of consecutive naturals, for example, 529838011 + ... + 529838050.

It is an arithmetic number, because the mean of its divisors is an integer number (3708866217).

Almost surely, 2^21193521220 is an apocalyptic number.

21193521220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21193521220 is an abundant number, since it is smaller than the sum of its proper divisors (23312873384).

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

21193521220 is a wasteful number, since it uses less digits than its factorization.

21193521220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059676070 (or 1059676068 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The spelling of 21193521220 in words is "twenty-one billion, one hundred ninety-three million, five hundred twenty-one thousand, two hundred twenty".