21201001201220 has 24 divisors (see below), whose sum is σ = 44522936199000. Its totient is φ = 8480241684992.

The previous prime is 21201001201213. The next prime is 21201001201271. The reversal of 21201001201220 is 2210210010212.

It can be written as a sum of positive squares in 4 ways, for example, as 1574116511044 + 19626884690176 = 1254638^2 + 4430224^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21201001201195 and 21201001201204.

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, 8826965 + ... + 10968924.

It is an arithmetic number, because the mean of its divisors is an integer number (1855122341625).

Almost surely, 2^{21201001201220} is an apocalyptic number.

21201001201220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201001201220 is an abundant number, since it is smaller than the sum of its proper divisors (23321934997780).

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

21201001201220 is a wasteful number, since it uses less digits than its factorization.

21201001201220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19849447 (or 19849445 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21201001201220 its reverse (2210210010212), we get a palindrome (23411211211432).

The spelling of 21201001201220 in words is "twenty-one trillion, two hundred one billion, one million, two hundred one thousand, two hundred twenty".