21727731101 has 4 divisors (see below), whose sum is σ = 22257675804. Its totient is φ = 21197786400.

The previous prime is 21727731007. The next prime is 21727731107. The reversal of 21727731101 is 10113772712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10434418201 + 11293312900 = 102149^2 + 106270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21727731101 - 2¹⁰ = 21727730077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21727731107) 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, 264972290 + ... + 264972371.

It is an arithmetic number, because the mean of its divisors is an integer number (5564418951).

Almost surely, 2^21727731101 is an apocalyptic number.

It is an amenable number.

21727731101 is a deficient number, since it is larger than the sum of its proper divisors (529944703).

21727731101 is an equidigital number, since it uses as much as digits as its factorization.

21727731101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 529944702.

The product of its (nonzero) digits is 4116, while the sum is 32.

The spelling of 21727731101 in words is "twenty-one billion, seven hundred twenty-seven million, seven hundred thirty-one thousand, one hundred one".