21210011001220 has 48 divisors (see below), whose sum is σ = 44704455663168. Its totient is φ = 8452882500480.

The previous prime is 21210011001203. The next prime is 21210011001251. The reversal of 21210011001220 is 2210011001212.

It is a self number, because there is not a number n which added to its sum of digits gives 21210011001220.

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, 42240030 + ... + 42739210.

It is an arithmetic number, because the mean of its divisors is an integer number (931342826316).

Almost surely, 2^{21210011001220} is an apocalyptic number.

21210011001220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210011001220 is an abundant number, since it is smaller than the sum of its proper divisors (23494444661948).

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

21210011001220 is a wasteful number, since it uses less digits than its factorization.

21210011001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506980 (or 506978 counting only the distinct ones).

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

Adding to 21210011001220 its reverse (2210011001212), we get a palindrome (23420022002432).

The spelling of 21210011001220 in words is "twenty-one trillion, two hundred ten billion, eleven million, one thousand, two hundred twenty".