21001011201220 has 48 divisors (see below), whose sum is σ = 44864736618240. Its totient is φ = 8256193652736.

The previous prime is 21001011201119. The next prime is 21001011201253. The reversal of 21001011201220 is 2210211010012.

It is a self number, because there is not a number n which added to its sum of digits gives 21001011201220.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32454780 + ... + 33095539.

It is an arithmetic number, because the mean of its divisors is an integer number (934682012880).

Almost surely, 2^{21001011201220} is an apocalyptic number.

21001011201220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001011201220 is an abundant number, since it is smaller than the sum of its proper divisors (23863725417020).

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

21001011201220 is a wasteful number, since it uses less digits than its factorization.

21001011201220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65550604 (or 65550602 counting only the distinct ones).

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

Adding to 21001011201220 its reverse (2210211010012), we get a palindrome (23211222211232).

The spelling of 21001011201220 in words is "twenty-one trillion, one billion, eleven million, two hundred one thousand, two hundred twenty".