21080220164 has 12 divisors (see below), whose sum is σ = 36990906624. Its totient is φ = 10511389704.

The previous prime is 21080220163. The next prime is 21080220169. The reversal of 21080220164 is 46102208012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21080220163) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7178444 + ... + 7181379.

It is an arithmetic number, because the mean of its divisors is an integer number (3082575552).

Almost surely, 2^21080220164 is an apocalyptic number.

It is an amenable number.

21080220164 is a deficient number, since it is larger than the sum of its proper divisors (15910686460).

21080220164 is a wasteful number, since it uses less digits than its factorization.

21080220164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14360194 (or 14360192 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

Adding to 21080220164 its reverse (46102208012), we get a palindrome (67182428176).

The spelling of 21080220164 in words is "twenty-one billion, eighty million, two hundred twenty thousand, one hundred sixty-four".