21671100100 has 36 divisors (see below), whose sum is σ = 50643696964. Its totient is φ = 8001636480.

The previous prime is 21671100071. The next prime is 21671100103. The reversal of 21671100100 is 100117612.

It can be written as a sum of positive squares in 6 ways, for example, as 5048670916 + 16622429184 = 71054^2 + 128928^2 .

It is not an unprimeable number, because it can be changed into a prime (21671100103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8333739 + ... + 8336338.

Almost surely, 2^21671100100 is an apocalyptic number.

21671100100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21671100100 is an abundant number, since it is smaller than the sum of its proper divisors (28972596864).

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

21671100100 is a wasteful number, since it uses less digits than its factorization.

21671100100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16670104 (or 16670097 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 19.

Adding to 21671100100 its reverse (100117612), we get a palindrome (21771217712).

It can be divided in two parts, 21671 and 100100, that added together give a triangular number (121771 = T₄₉₃).

The spelling of 21671100100 in words is "twenty-one billion, six hundred seventy-one million, one hundred thousand, one hundred".