21210121100020 has 24 divisors (see below), whose sum is σ = 44563228373664. Its totient is φ = 8479862904096.

The previous prime is 21210121100011. The next prime is 21210121100033. The reversal of 21210121100020 is 2000112101212.

It is a super-2 number, since 2×21210121100020² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 261554442 + ... + 261635521.

It is an arithmetic number, because the mean of its divisors is an integer number (1856801182236).

Almost surely, 2^{21210121100020} is an apocalyptic number.

21210121100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210121100020 is an abundant number, since it is smaller than the sum of its proper divisors (23353107273644).

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

21210121100020 is a wasteful number, since it uses less digits than its factorization.

21210121100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523191999 (or 523191997 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21210121100020 its reverse (2000112101212), we get a palindrome (23210233201232).

The spelling of 21210121100020 in words is "twenty-one trillion, two hundred ten billion, one hundred twenty-one million, one hundred thousand, twenty".