21210100200 has 72 divisors (see below), whose sum is σ = 71230592550. Its totient is φ = 5656026240.

The previous prime is 21210100193. The next prime is 21210100207. The reversal of 21210100200 is 200101212.

It is an interprime number because it is at equal distance from previous prime (21210100193) and next prime (21210100207).

It can be written as a sum of positive squares in 3 ways, for example, as 15684556644 + 5525543556 = 125238^2 + 74334^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21210100207) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5889895 + ... + 5893494.

Almost surely, 2^21210100200 is an apocalyptic number.

21210100200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210100200 is an abundant number, since it is smaller than the sum of its proper divisors (50020492350).

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

21210100200 is a wasteful number, since it uses less digits than its factorization.

21210100200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11783411 (or 11783399 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21210100200 its reverse (200101212), we get a palindrome (21410201412).

The spelling of 21210100200 in words is "twenty-one billion, two hundred ten million, one hundred thousand, two hundred".