21271010166 has 48 divisors (see below), whose sum is σ = 53955746208. Its totient is φ = 5929200000.

The previous prime is 21271010143. The next prime is 21271010171. The reversal of 21271010166 is 66101017212.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2053585 + ... + 2063916.

It is an arithmetic number, because the mean of its divisors is an integer number (1124078046).

Almost surely, 2^21271010166 is an apocalyptic number.

21271010166 is an abundant number, since it is smaller than the sum of its proper divisors (32684736042).

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

21271010166 is a wasteful number, since it uses less digits than its factorization.

21271010166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4117557 (or 4117554 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

Adding to 21271010166 its reverse (66101017212), we get a palindrome (87372027378).

The spelling of 21271010166 in words is "twenty-one billion, two hundred seventy-one million, ten thousand, one hundred sixty-six".