21816433220 has 24 divisors (see below), whose sum is σ = 45821298264. Its totient is φ = 8725280256.

The previous prime is 21816433211. The next prime is 21816433277. The reversal of 21816433220 is 2233461812.

It can be written as a sum of positive squares in 4 ways, for example, as 12452774464 + 9363658756 = 111592^2 + 96766^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63854 + ... + 218426.

It is an arithmetic number, because the mean of its divisors is an integer number (1909220761).

Almost surely, 2^21816433220 is an apocalyptic number.

21816433220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21816433220 is an abundant number, since it is smaller than the sum of its proper divisors (24004865044).

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

21816433220 is a wasteful number, since it uses less digits than its factorization.

21816433220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161639 (or 161637 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The spelling of 21816433220 in words is "twenty-one billion, eight hundred sixteen million, four hundred thirty-three thousand, two hundred twenty".