21728722236 has 48 divisors (see below), whose sum is σ = 56483162400. Its totient is φ = 6455215872.

The previous prime is 21728722199. The next prime is 21728722247. The reversal of 21728722236 is 63222782712.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2396971 + ... + 2406018.

It is an arithmetic number, because the mean of its divisors is an integer number (1176732550).

Almost surely, 2^21728722236 is an apocalyptic number.

21728722236 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21728722236 is an abundant number, since it is smaller than the sum of its proper divisors (34754440164).

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

21728722236 is a wasteful number, since it uses less digits than its factorization.

21728722236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4803038 (or 4803036 counting only the distinct ones).

The product of its digits is 225792, while the sum is 42.

The spelling of 21728722236 in words is "twenty-one billion, seven hundred twenty-eight million, seven hundred twenty-two thousand, two hundred thirty-six".