21220555161 has 16 divisors (see below), whose sum is σ = 30473938880. Its totient is φ = 13057346880.

The previous prime is 21220555087. The next prime is 21220555163. The reversal of 21220555161 is 16155502212.

It is not a de Polignac number, because 21220555161 - 2¹³ = 21220546969 is a prime.

It is a super-2 number, since 2×21220555161² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21220555163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 401751 + ... + 451491.

It is an arithmetic number, because the mean of its divisors is an integer number (1904621180).

Almost surely, 2^21220555161 is an apocalyptic number.

It is an amenable number.

21220555161 is a deficient number, since it is larger than the sum of its proper divisors (9253383719).

21220555161 is a wasteful number, since it uses less digits than its factorization.

21220555161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60696.

The product of its (nonzero) digits is 6000, while the sum is 30.

The spelling of 21220555161 in words is "twenty-one billion, two hundred twenty million, five hundred fifty-five thousand, one hundred sixty-one".