21210100100 has 36 divisors (see below), whose sum is σ = 52601049984. Its totient is φ = 7272034080.

The previous prime is 21210100081. The next prime is 21210100111. The reversal of 21210100100 is 100101212.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15149372 + ... + 15150771.

Almost surely, 2^21210100100 is an apocalyptic number.

21210100100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210100100 is an abundant number, since it is smaller than the sum of its proper divisors (31390949884).

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

21210100100 is a wasteful number, since it uses less digits than its factorization.

21210100100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30300164 (or 30300157 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21210100100 its reverse (100101212), we get a palindrome (21310201312).

The spelling of 21210100100 in words is "twenty-one billion, two hundred ten million, one hundred thousand, one hundred".