21202121100 has 72 divisors (see below), whose sum is σ = 63002804368. Its totient is φ = 5501088000.

The previous prime is 21202121077. The next prime is 21202121111. The reversal of 21202121100 is 112120212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 943951 + ... + 966150.

Almost surely, 2^21202121100 is an apocalyptic number.

21202121100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202121100 is an abundant number, since it is smaller than the sum of its proper divisors (41800683268).

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

21202121100 is a wasteful number, since it uses less digits than its factorization.

21202121100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1910155 (or 1910148 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21202121100 its reverse (112120212), we get a palindrome (21314241312).

The spelling of 21202121100 in words is "twenty-one billion, two hundred two million, one hundred twenty-one thousand, one hundred".