21212011001220 has 48 divisors (see below), whose sum is σ = 63962371636800. Its totient is φ = 5221418092416.

The previous prime is 21212011001213. The next prime is 21212011001257. The reversal of 21212011001220 is 2210011021212.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21212011001220.

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, 13597442170 + ... + 13597443729.

It is an arithmetic number, because the mean of its divisors is an integer number (1332549409100).

Almost surely, 2^{21212011001220} is an apocalyptic number.

21212011001220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212011001220 is an abundant number, since it is smaller than the sum of its proper divisors (42750360635580).

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

21212011001220 is a wasteful number, since it uses less digits than its factorization.

21212011001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27194885924 (or 27194885922 counting only the distinct ones).

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

Adding to 21212011001220 its reverse (2210011021212), we get a palindrome (23422022022432).

The spelling of 21212011001220 in words is "twenty-one trillion, two hundred twelve billion, eleven million, one thousand, two hundred twenty".