21728305011 has 8 divisors (see below), whose sum is σ = 33109798144. Its totient is φ = 12416174280.

The previous prime is 21728305009. The next prime is 21728305021. The reversal of 21728305011 is 11050382712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21728305011 - 2¹ = 21728305009 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21728305011.

It is not an unprimeable number, because it can be changed into a prime (21728305021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 517340575 + ... + 517340616.

It is an arithmetic number, because the mean of its divisors is an integer number (4138724768).

Almost surely, 2^21728305011 is an apocalyptic number.

21728305011 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21728305011 is a deficient number, since it is larger than the sum of its proper divisors (11381493133).

21728305011 is a wasteful number, since it uses less digits than its factorization.

21728305011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034681201.

The product of its (nonzero) digits is 3360, while the sum is 30.

Adding to 21728305011 its reverse (11050382712), we get a palindrome (32778687723).

The spelling of 21728305011 in words is "twenty-one billion, seven hundred twenty-eight million, three hundred five thousand, eleven".