21121001101020 has 96 divisors (see below), whose sum is σ = 59332809070080. Its totient is φ = 5613792559360.

The previous prime is 21121001100919. The next prime is 21121001101021. The reversal of 21121001101020 is 2010110012112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21121001100987 and 21121001101005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121001101021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 410736871 + ... + 410788289.

It is an arithmetic number, because the mean of its divisors is an integer number (618050094480).

Almost surely, 2^{21121001101020} is an apocalyptic number.

21121001101020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121001101020 is an abundant number, since it is smaller than the sum of its proper divisors (38211807969060).

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

21121001101020 is a wasteful number, since it uses less digits than its factorization.

21121001101020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73755 (or 73753 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21121001101020 its reverse (2010110012112), we get a palindrome (23131111113132).

The spelling of 21121001101020 in words is "twenty-one trillion, one hundred twenty-one billion, one million, one hundred one thousand, twenty".