21201211102020 has 96 divisors (see below), whose sum is σ = 60978246771456. Its totient is φ = 5499912844800.

The previous prime is 21201211102007. The next prime is 21201211102067. The reversal of 21201211102020 is 2020111210212.

It is a super-2 number, since 2×21201211102020² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12196705 + ... + 13826135.

It is an arithmetic number, because the mean of its divisors is an integer number (635190070536).

Almost surely, 2^{21201211102020} is an apocalyptic number.

21201211102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21201211102020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30489123385728).

21201211102020 is an abundant number, since it is smaller than the sum of its proper divisors (39777035669436).

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

21201211102020 is a wasteful number, since it uses less digits than its factorization.

21201211102020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1635341 (or 1635339 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21201211102020 its reverse (2020111210212), we get a palindrome (23221322312232).

The spelling of 21201211102020 in words is "twenty-one trillion, two hundred one billion, two hundred eleven million, one hundred two thousand, twenty".